Signs saying "Private Property - Keep Out" are increasingly commonplace these days, particularly in the countryside, as landowners seek to resist the assertion by Keep Ireland Open that everyone has a right to roam. But what about the partial privatisation of public spaces in the city?

It was ironic that the Central Bank should celebrate the completion of a £1 million re-ordering of its plaza on Dame Street, including the closure of its granite steps to the public, as controversy erupted over a longstanding plan by Senator David Norris to re-erect the gates of Santry Court in North Great George's Street.

The two cases are not precisely analogous. The Central Bank plaza is owned by the bank, so public access to it - however generous over the past 20 years - is by grace and favour. North Great George's Street, on the other hand, has been a public thoroughfare for more than 230 years - and many feel it should stay that way.

The Central Bank's decision to enclose its steps with railings was perfectly understandable: although they provided a gathering place for young people, abuses included graffiti, evidence of drug-taking and public urination. According to Hugh O'Donnell, the bank's head of corporate services, not even power-hosing was enough to get rid of the ingrained scars. Every weekend the south-facing steps were strewn with bottles and beer cans, while used condoms and syringes could be found in the adjoining shrubbery.

The granite steps have never looked as pristine as they do today, while the shrubbery that once provided so many nooks and crannies has been replaced by lush green grass, which must have been ordered by the square metre, like a carpet: "It's the only grass in Temple Bar," the architect, Sam Stephenson, wryly observed.

At a cost of £1 million-plus, the Central Bank has eliminated a perennial maintenance problem by erecting a U-shaped set of railings, linked to accommodate Eamon O'Doherty's Crann an Oir sculpture, in an oddly neo-Baroque style that seems somewhat at odds with its towering modernist tour de force from 1980.

To compensate for the removal of public access to the steps, the plaza has been opened up by removing the box-like fountain at the corner of Fownes Street - actually, a fire escape from the bank's 120-space underground car-park - and providing more seating on easy-to-clean polished granite coping. An air intake vent is concealed under a long, low, rectangular stone seat on the Fownes Street corner, while the extract is housed in a bulky structure nearby. Cladding it in timber, with matching skirts for the trees, was an unusual choice; even the bank concedes that opinion on this element of the scheme is divided "50/50".

The idea was to provide comfortable backs for the seating, though there must be less incongruous ways of achieving that result. Dunwoody and Dobson, the main contractors, had a tough task trying to get the iroko planking right, especially around the trees, since it called for the type of skills once used to make beer barrels.

As for the neo-Baroque railings, Hugh O'Donnell, the bank's head of corporate affairs, said the aim was to avoid a "straight-up, barracks-type feel" - like the taller, vertical railings to the rear. Perhaps the bank should now be turning its attention to measures that would mitigate the wind-tunnel effects created by its headquarters.

Dublin Corporation's decision to grant planning permission for the re-ordering of the Central Bank plaza in February, 1999, was uncontested. Not so its adoption of Senator Norris's plan to enclose the southern end of North Great George's Street, approximately 25 metres from its junction with rather less salubrious Parnell Street.

The plan is being promoted as a public project under Part 10 of the 1994 Planning Regulations by the Roads and Streets Department of the Corporation. It will be adjudicated on by the Planning Department and, ultimately, by the City Council. Whatever its decision, the process does not allow for appeals to An Bord Pleanala.

Mr Norris has denied that the plan, first proposed some 12 years ago by him as chairman of the North Great George's Street Preservation Society, is elitist in its inspiration and he has labelled its critics as "inverted snobs" who had said "nothing at all" when other streets in the city were closed to vehicular traffic.

An Taisce has been quite restrained, perhaps because it does not wish to part company with a fellow-conservationist; it will be submitting a "mild objection" to the scheme, according to its chairman, Michael Smith. But others take a much stronger line, based on the principle that a public street should not be railed off.

Professor Kevin B Nowlan, veteran conservationist and chairman of the Dublin Civic Group, is "totally against" the plan. "It's a very clear street, leading up to Belvedere House, flanked by these fine houses. To put in gates is both socially and architecturally objectionable, and I think it's most regrettable that this proposition was made."

Brian Walsh, a resident of North Great George's Street for 15 years, is "vehemently opposed" to the plan, describing it as "an arrogant proposal which seeks to isolate us into some form of quasi-suburb in the midst of a regenerating city", as a result of lobbying by "one committed individual" over a period of several years.

In a written objection sent to the corporation's planners - some of whom are also known to have serious reservations about the scheme - Mr Walsh said the street had played an integral part in the life of the city for more than 200 years. "It was not designed as a cul-de-sac and should not now turn its back on the city," he said.

He also noted that the proposed gates and railings are Regency in style and "bear no relationship to the 18th-century grandeur of either the street or Belvedere House".

They would be "puny" compared to the "scale, girth and craftsmanship" of Georgian railings, such as those on the Merrion Square front of Leinster House.

The drawings by John O'Connell, the noted conservation architect and resident of the street, date from 1988 and show the elevation, plan and sections of the proposed railings on two sheets. It is likely that Dublin Corporation's planners will be seek further information, including photo-montages, to assess the visual impact.

Mr O'Connell said the set of gates, which would be mounted on a short flight of granite steps, would provide something more pleasant for the eye to rest on than the "terrible vista" looking south towards what he calls the "Divan Building" - the eight-storey slab of pre-cast concrete "bed-ends" called Telephone House.

But the argument advanced by Mr Norris that gates are shown at the southern end of the street on Rocque's map of Dublin in 1756 is surely a red herring. These gates marked the entrance to an avenue leading to the local manor house, Mount Eccles, which was demolished when the street was developed from the 1770s onwards.

What Dublin architect Sean Kearns finds very disturbing is that the corporation would adopt such a divisive proposal "at the behest of a small group of people" in the midst of a planning crisis when its planners are trying to cope with so many other demands. Part 10, in his view, should only be used for projects that benefit the city.