The holding of parent-teacher meetings outside school hours is one of the major sticking points in negotiations on the payment of benchmarking awards.
The recommended pay rises, which average 8.9 per cent, are contingent on unions agreeing to changes in work practices and on a stable industrial relations climate.
While the teachers' unions have made some progress on issues such as the standardisation of the school year, there has been strong opposition to the plan to move parent-teacher meetings outside normal school hours.
This change would facilitate the growing number of parents working outside the home. "That is the big stumbling block," said one source yesterday.
"The Minister for Education is adamant that he wants total flexibility on this. It could be enough to blow the national agreement out of the water."
Teachers have expressed concern over safety and security issues that may arise in schools at night-time.
Their concerns relate to small schools in isolated areas, where only one or two teachers may be present, and schools in disadvantaged urban areas where teachers' safety may be at risk.
Meanwhile, ICTU's general secretary, Mr David Begg, said yesterday that the pay terms of the proposed new national partnership deal were "satisfactory" and would beat inflation by a half to one per cent.
This would give a real rise in the standard of living, he said on RTÉ's This Week programme. The proposed pay deal would deliver 7.2 per cent over 18 months.
Public service unions and department officials will resume negotiations this afternoon on the Programme for Modernisation and Change, which must be agreed before the final 75 per cent of the benchmarking pay rises are sanctioned.
The Government has agreed to backdate the first 25 per cent of the benchmarking awards to December 2001.
Subject to final agreement on the modernisation programme, another 50 per cent will be awarded from January 1st, 2004, while the final 25 per cent will be paid from June 1st, 2005.
The talks are likely to continue tomorrow and possibly on Wednesday.
A Department of Finance spokesman said "some progress" had been made in the weekend talks.
Public service unions have already expressed concern over proposed recruitment and promotion issues. The Programme for Modernisation and Change proposes opening more recruitment opportunities to the public, instead of confining them to internal competition. This would affect promotional opportunities for public and civil servants.
Concerns have also been expressed over the proposed introduction of more disciplinary rules for what the report describes as "serious cases of under-performance".
Health workers have expressed concern over a clause that industrial action cannot be threatened while issues are being processed through agreed procedures.
The Programme for Modernisation and Change proposes a more accessible health service, with longer opening hours for the public.
Local government offices and other public facilities would also have to extend their opening hours to improve services.
The standardisation of school holidays has been sought for some time, as parents with children in different schools often have to take time off on separate weeks to facilitate different mid-term and Christmas breaks.
The benchmarking talks resume as unions and employers contemplate the terms of the proposed new national partnership deal.
ICTU's Mr Begg said on RTÉ radio yesterday: "There is very little doubt in my mind that certain employments in the private sector could get pay increases in excess of the terms of this agreement, but there are certain employments who wouldn't get anything at all and certain employments who would get less."
He estimated there was about 10 days to a fortnight's work in completing the social agenda aspect of the partnership talks.