The EIS and the Scottish Secondary Teachers' Association issued separate statements urging finance secretary John Swinney and education secretary Michael Russell to stop stalling and make a firm proposal on the future design of the Scottish Teachers' Superannuation Scheme.
Both unions have suspended industrial action in order to try and reach a Scottish solution to the UK government's pensions reforms.
Earlier this week, however, EIS general secretary Larry Flanagan warned that the patience of the teaching profession was becoming increasingly thin. SSTA acting general secretary Alan McKenzie said it was "now time for the Scottish government to put up or shut up".
Signs have since emerged, however, that the government's postponement of the meeting may signal that it is still working to find a way of improving the pensions terms for Scottish teachers compared to their colleagues south of the border.
Drew Morrice, EIS assistant secretary and one of the lead negotiators on the teachers' side, told TESS: "The crux of making progress depends on softening the landing for people who choose to retire at 65 rather than an arbitrary retirement age."
The meeting scheduled for this week is not now expected to take place until mid-December.
A Scottish government spokeswoman said: "As much of pensions policy and legislation is currently reserved to Westminster, the Scottish government has sought clarity from the UK government over a number of months on the scope available to Scottish ministers to conclude these negotiations in line with Scottish circumstances."
She went on to say: "That information has only recently become clear and ministers are considering this detail. We will make our position clear on those issues at the earliest opportunity."