The old sod plays its part at the Venice Biennale

Improbable as it may seem, Ireland's first ever pavilion at the prestigious Venice Biennale, which opened at the weekend, is made from 21 tonnes of Bord na Mona peat briquettes. But what a talking point it became, at least among the few who saw Tom de Paor's "allegorical construction".

Described by its inventive young architect as "a sensory pavilion" and, more obscurely, as "a speculation on land", this room-sized installation titled N3 (N to the power of three) and measuring some 3.5 cubic metres, simultaneously evokes the Gallarus oratory, neolithic passage tombs and even Catholic confessionals.

It is certainly a feather in the cap of this architect, a brilliant lateral thinker whose best-known work to date has probably been the Eden restaurant in Dublin's Temple Bar. More recently, he was commissioned to design the largest environmental installation for a motorway in Britain on the A13 at Barking, near London.

Consisting of some 1,600 bales of briquettes, assembled to form what the 33-year-old de Paor calls "a slumped cube", it looks surprisingly small when you see it first. But, just like the Casino at Marino in Dublin, this intriguing pile of compressed turf contains hidden delights - two corbelled passages and a central "chamber" open to the sky.

Looked at on plan, these three elements form the letter "N", something of an obsession for the architect. It is a reference to St Nicholas of Myra (also known as Santa Claus), who is commemorated by impressive churches both in Dublin and Venice; coincidentally, there is a turf yard beside the saint's church in Francis Street.

St Nicholas is the patron saint of children, virgins, apothecaries, pawn brokers (remember the three golden balls?), perfumiers and, according to de Paor, property developers. The latter, he complains, include those who had built such "crap" apartment blocks in the Liberties and elsewhere in Dublin.

Few visitors will get the message that he has these developers within his sights through N3. The installation is devoid of any written explanation on its remotely-located site at Baccini, some 20 minutes by vaporetto from the main Biennale site at the Giardini di Castello. A brief text would certainly help visitors unfamiliar with Ireland.

The Croats made a much better fist of publicising their remotely-located exhibition in the Dorsoduro area of the city, entitled "Transparency of the Hyperreal". Their most provocative slogan was "No scale - no typology - no style" (what's left?), and everyone who entered the Giardini was given an explanatory leaflet.

De Paor's own description of his project suggests that he has transformed a pile of turf into an "intelligent structure" with allegorical references to "a multitude of memories in the Irish psyche: turf-cutting, territorial rights, land, its sale and commodification" - all compressed, as it were, in a bale of briquettes. It is also a symbolic gift from "the land-rich island of Ireland to the land-hungry island-city of Venice". After the Biennale ends in October, the 40,000-odd briquettes will be saturated in water and used as compost for the watery city's gardens or mixed into the landfill for an extension to its cemetery island of San Michele.

"It's a very Irish thing to do," says de Paor, who was commissioned to carry out this unique project by the Cultural Relations Committee of the Department of Foreign Affairs, with financial support from the Arts Council. All of the briquettes were supplied free by Bord na Mona and shipped to Venice courtesy of Beverly Smith. N3 was built in six sweltering days by two of de Paor's colleagues, Stephen Short and John Cullen, on the patio of a sculpture garden at the Thetis scientific research centre at Baccini, where the Venetian Republic once turned out a new ship every 12 days.

Only three or four people can fit into the pavilion at a time. The entrance and exit passages are so narrow that you have to squeeze in sideways. They are also suffused by the smell of compressed turf. It is strangely sweet, but no amount of sniffing can quite pin it down.

Inside, there is a "contemplation seat", also made from briquettes, where visitors may collect nine small Pokemon-style cards featuring unidentified images of Ireland and, obversely, of Venice. Quite what they will make of these offerings, laid out on a tray cast from yellow rubber mimicking a bale of briquetttes, is anybody's guess.

Although Raymund Ryan, the architect and critic who is Irish Commissioner for the Venice Biennale, sees N3 as the symbolic foundation for an official Irish pavilion at the Venice Biennale, it is unlikely to be seen by more than a fraction of the madding crowds in the Giardini. Publicity is almost imperceptible, and there is even talk of dismantling it at the end of July, when the site will close for the holidays. Given that Irish architects are holding their annual conference in Verona in October, it would be a crying shame if those who go on to the Biennale don't get a chance to see it.