The Education Minister, Brian Wilson, told the conference he was keeping "an open mind" on the future of the pay bargaining machinery.
The union has been one of the most vociferous opponents of the Scottish Joint Negotiating Committee, which is dominated by the Educational Institute of Scotland.
This year's conference once again criticised "the repeated failure of the SJNC to match the salary awards of (the review body) in England and Wales." The result is that there was now "a disincentive to teach in Scotland," delegates were told.
The NAS has been joined by the Association of Directors of Education who point out that teachers' pay awards have been below average earnings in 25 out of the last 26 years. The only signficant increases have been gained on the three occasions following special inquiries into teachers' pay.
The directors blame what they regard as the inflexible and centralist nature of the SJNC whose agreements are legally binding.
A number of the issues being discussed by unions and education authorities in their joint millennium review, dealing with pay, conditions, promoted posts and management, will have to be thrashed out in the SJNC before any final agreement is possible.
Mr Wilson said he was aware of the dissatisfaction with the SJNC but he preferred to keep an open mind for the time being. "I will be paying close attention to what the millennium review has to say about the future of collective bargaining for the teaching profession," he added.
The Minister confined his main remarks to reiterating the Secretary of State's call for a shake-up of the promoted post structure, particularly in secondary schools where more than 50 per cent of teachers are in promoted posts. The Government has a manifesto commitment for a promotion system aimed at rewarding good teachers to stay in the classroom.
The Scottish Office now takes the view that the present structure does not support the drive to raise standards as ambitious teachers can only earn more by opting for promotion out of the classroom.
"It cannot be right to continue to take our most experienced teachers and burden them with administration when they are the very people who should be taking the most direct responsibility for teaching and learning," Mr Wilson told the conference.
The EIS points out, however, that the present promoted posts have been largely created by Scottish Office circulars. Ironically the exception, which was the subject of an SJNC agreement, was the senior teacher post. It was created in the wake of the last major industrial dispute in the mid-1980s specifically to reward good teachers to stay in the classroom.