"WHEN is a job not a job?" When you can be laid off without notice, perhaps? Or when you don't qualify for the company pension scheme or the sick pay scheme, or the company maternity leave scheme? When you work 48 hours a week, SO weeks a year, but your bank cannot give you a mortgage because you have no employment contract? When you earn less than your colleagues for the same work, or get no overtime, or holiday pay?

Work where these conditions apply is increasingly common - work in which employees vie with one another for hours, don't claim sick pay they are entitled to in the well founded fear that their hours may be cut; get little or no notice of their starting and finishing times; and don't know how much they will take home from week to week.

Extreme versions of these conditions drove the Dunnes Stores workers to strike in 1995, and tales of such practices sparked huge public sympathy for their cause. But while zero hour contracts ("we guarantee you no hours but we might give you as many as you can work") have been wiped out at Dunnes, similar conditions are common throughout the retail industry, in hotels, catering, contract cleaning, nursing, the fast food industry and journalism.

Most casual workers feel so vulnerable to having their hours cut or scratched that they do not demand even the limited rights they may have through paying PRSI or under part time workers legislation.

The prevalence of temporary and casual working has angered nurses, for instance, to the point that it is a central plank in their current dispute.

In many hospitals outside Dublin, nurses who apply for, but don't win, permanent jobs are put on a list - a panel, which usually has a lifetime of a year - to be called in if other permanent jobs become available. But in reality, the panel is also used to source casual workers, says Leonore Mrkwicka, assistant general secretary of the Irish Nurses' Organisation.

"The health boards do not tell people where they are on the panel, or the size of the panel - and it can be very large and the jobs very few - so nurses stay in the area hoping to get a job when there is really no point," explains Mrkwicka. "Then the hospital has plenty of temporary nurses available.

"I have no doubt they are not telling people their placing on the panel because it's very handy for them," she says.

It is not so handy for the nurses who must take what work is available, when it is available. "If they don't go in, they feel they will be affected and perhaps not get called in next time," says Mrkwicka. "They are being intimidated into dropping everything ... and then when they get in they may Lind they are, only needed for four hours.

Mrkwicka mentions that it is not unusual for such nurses to have to or 15 years' experience, but as casual staff they cannot get beyond half way up the rising pay scale for nurses.

"We recognise that there is a need for some temporary or casual nurses, but there are far more than there should be," she says. "This is gross exploitation of committed, dedicated professionals and they are being treated abominably, being left to swing on the end of the telephone. "It's no wonder nurses are leaving the country and the profession," she adds.

Employers believe a casualised workforce gives them a competitive advantage: the unions counter that most of the employers relying heavily on such flexibility are competing in the domestic and not the international market, and so the advantage is illusory.

"This advantage is not based on greater efficiency or on better methods of working, but on forcing workers to compete against each other," says Maurice Sheehan of the union Mandate.

But the Irish Business and Employers' Confederation (IBEC) strongly objects to current efforts to introduce controls on zero hour working.

"Flexibility can suit workers as well as employers," says IBEC social affairs executive, Aileen O'Donoghue. "And if the other option is being unemployed...

"For many people, casual work means maintaining a foothold in the labour market and the mentality of work," she adds. "If you start putting restrictions, on casual work, the impact on the employee is quite significant.

James Wickham, a senior lecturer in sociology at Trinity College, Dublin, says employers are certainly not introducing flexible or random hours to benefit their employees. "Irish employers are not interested in developing their human resources," he says. "They always want to go for the low cost option."

He talked in depth to employers for a study for the European Foundation for the Improvement of Working and Living Conditions in 1995 - a study he says has not yet been superseded - and found that where Irish firms use part timers or casual workers, these make up a much larger proportion of the workforce than is normal in other countries.

His study also found that a significant number of part time or casual workers rather than being the mothers with young children that might be imagined are in fact people who want full time jobs but are taking what work they can get. And although some sorts of flexibility can benefit both employer and employee, he says that even among those who prefer part time work, nobody wants random hours - "that only suits employers".

BUT whether employers actually benefit in the long run may be questionable, according to Professor of Psychology Ciaran O'Boyle of the Royal College of Surgeons. "In current management thinking the team is felt to be the most effective unit in terms of quality management - but you are very unlikely to get team work going in an organisation where individuals are competing against each other for jobs and security," he says.

Certainly, casual employment can cause extra stress for the workers, he adds. "Any situation that is unpredictable or uncontrollable can be very stressful, depending on the individual so casualised work can be potentially significantly more stressful than regular work," he says.

"This is particularly clear if you look at what drives people to work in the first place. The basics we need from a job are that it provides food and shelter and after that other needs come into play. These are the need for security, the need for affiliation - the need to belong and be part of a group - and the need to develop your potential.

"It's very difficult in a casual work situation for these needs to be fulfilled. People will look elsewhere for those needs to be fulfilled, perhaps to family or sport or leisure activities, or perhaps to industrial relations.

The possibility of change lies in legislation included in the Government's Working Hours Bill, now at committee stage, and in the more distant future from the EU. MEP Brian Crowley, a member of the European Social Affairs Committee, says it is one of the subjects on the committee's agenda at the moment - and that now, not later, is the time to lobby the EU on the subject.

He says part time working is simply a reality throughout Europe, and that his priority now would be ensuring that rights and sickness benefits for such workers should be the same as for full time workers, as well as derogations for employers for seasonal working, for example, or when workers granted free negotiation don't want the directive to apply to them.