The national pay deal is under considerable pre-election strain, most notably from the nurses who have been tentatively joined this past week by secondary school teachers.

What's niggling the teachers?

Their involvement is hardly surprising - the Association of Secondary Teachers, Ireland (ASTI) closed down the schools prior to the last general election in 2002 in an ultimately fruitless attempt to extract additional pay increases from the government.

At its conference in Sligo last week, ASTI passed an emergency motion demanding the national pay agreement, Towards 2016, which pays 4.5% a year to all workers, be re-negotiated. With inflation tipping over 5% yet again, ASTI said workers were worse off with what is supposed to be a cost-of-living pay increase. Concluded late last year when inflation was under 4%, the steady rise since then has turned the national pay rise into a pay cut.

The following day, in yet another emergency motion, the ASTI backed "the right" of the nurses to pursue their demand for a 10.5% pay increase and a 35-hour week outside of benchmarking and the existing partnership process. The Teachers' Union of Ireland, at its conference in Donegal, similarly backed a motion supporting the nurses' pay campaign. However, both unions are working within partnership while simultaneously goading the nurses to fight the government for an even better deal from which, presumably, the teachers could benefit. The third and most powerful of the teacher unions, the INTO, has held its fire.

But doesn't benchmarking pay more to public servants on top of national pay increases?

Yes. What may be lost in the heat of the nurses' pay battle is that the national pay agreement contains two agreements. The main deal is for 10% over 27 months, or around 4.5% a year, and applies to all two million workers - public and private. But on top of that, the country's 270,000 public servants get extra pay increases about every four or five years under benchmarking.

Established in 2000, benchmarking was theoretically designed to ensure publicsector salaries kept pace with the private sector by 'benchmarking' public-sector jobs with comparable jobs in the private sector and adjusting pay accordingly. In reality, it was a sop to the powerful publicsector unions to end the near-pay-anarchy that had developed in the 1990s, when garda�, nurses and teachers took to the streets in support of ever increasing pay demands.

The unions can have no arguments about the pay awards under benchmarking and no explanation is offered as to how they decide on the awards. It's take it or leave it.

Privately, the unions could hardly believe their good fortune that the awarding of special pay rises to public servants was enshrined in government policy at a time when there was scant evidence to show that public servants were paid less than their private-sector colleagues. Indeed, economist Jim O'Leary, who was appointed to the first benchmarking body but controversially resigned before it produced its report in 2002, produced figures to show that public servants were at least 11% better off than private-sector workers.

So what's the problem, then, with the nurses and the teachers?

That is the Euro1bn question - the price the HSE put on the nurses' claim for a 10.5% pay increase and a 35-hour week.

In the last benchmarking pay report, produced in 2002, nurses were awarded increases of 8% for staff nurses and up to 16% for senior nurses. This is around about the average of 9% awarded across all grades. That 9% award cost the taxpayer Euro1.1bn in 2002 - a high price to pay for industrial peace in the public sector and more than the government forked out to secure peace in Northern Ireland.

Other groups got more under Benchmarking I - such as teachers (13%). But others, such as garda� (5%), prison officers (4%) and army privates(4%), got less.

The 10% available to all workers under Towards 2016 has also been offered to the nurses but they have turned that down on the basis that they can secure a better deal outside of partnership. The nurses have also refused to take part in a second benchmarking exercise, which produces its report in June. The irony here is that private-sector workers, who have to make do with a below inflation increase, would give their eye teeth for benchmarking. This may explain the less-than-ecstatic support for the nurses from private-sector unions. The public sector unions are even less supportive because the nurses' action threatens the very existence of benchmarking, which the unions will defend to the hilt.

Reading between the lines of the nurses' claim, it seems they are seeking a special pre-benchmarking pay deal before proceeding to benchmarking.

So are the nurses underpaid?

According to figures produced in the D�il before Easter, a staff nurse on the midpoint of their scale gets Euro36,981 a year. But when you add in premium payments and allowances this reaches Euro45,487. This compares to a physiotherapist on Euro42, 918 and a social worker on Euro49,141.

Everybody wants more money but the idea of benchmarking is that all claims are thrown, in an orderly fashion, into one pot where they are then assessed and decided upon by the independent Public Service Benchmarking Body in the one report.

The nurses' attempt to skirt that will bring down benchmarking and with it the national pay agreement and Taoiseach Bertie Ahern's beloved partnership. This explains Ahern's stern resistance to the nurses' pay claims, believing that facing off with the nurses so close to a general election is the (slightly) lesser of two evils. At this stage, the collapse of partnership is less palatable to the government.

But what about inflation - and the rest of the workers?

The incessant rise of inflation over the last six months poses a more serious longterm threat to partnership than the nurses' dispute. Speaking late last week, David Begg of Ictu acknowledged as much, saying that if inflation stays at over 5%, he will come under considerable pressure to re-negotiate.

Finance minister Brian Cowen has, however, ruled out a re-negotiation, claiming that it would be futile to push wages higher, in turn increasing inflation again