Pay gap warning to Scots unions
But the same mechanisms have failed to deliver on pay and should be scrapped, he said.
Mr de Gruchy said England and Wales had it "half right" in having an independent review body to make recommendations on pay. He favours a "side committee" of the review body with representatives from unions and management to investigate conditions of service.
The NAS will recommend a similar structure to the McCrone inquiry into Scottish teachers' pay and conditions.
Mr de Gruchy said he envied the limits to the working week in Scotland. "In England and Wales, teachers are working more than 50 hours a week, whereas if we were to adopt the Scottish context it would represent a big step forward," he said.
But Scottish teachers had fallen behind English teachers on pay and by next September could be further behind if unions in England do not block Government plans to raise average salaries by 9 per cent, putting most teachers on more than pound;25,000 a year. "It's there for the taking," he said.
Mr de Gruchy said his members had no voice on the Scottish Joint Negotiating Committee, dominated by the Educational Institute of Scotland.
"A review body would allow each union to submit evidence. The problem with the SJNC is that it's not a genuinely independent body. It cannot move without clearing matters with the Scottish Executive and the Treasury in London. The name of the game is how to get more money out of central government for teachers' pay and this kind of sham negotiating committee is not the best way.
"The review body gives above what the Government recommends and above what you can negotiate with employers."
The failure of the SJNC meant the EIS was now arguing for a "catch-up" payment because of the higher salaries paid in England and Wales.
Mr de Gruchy said there were strong benefits in having a United Kingdom union when it was clear that pay and conditions in Scotland mirrored those south of the border. "Basically, the Labour Party wants the same sort of things to happen throughout the UK," he said.
Tino Ferri, Scottish representative on the union's national executive, said he would "eat his hat" if the McCrone inquiry came up with something better than the failed Millennium Review. Mr Ferri also warned that children in some authorities face the prospect of part-time education because there are not have enough supply teachers to cover for absences.