Councils have been accused of spending millions of pounds to delay settling "legitimate" equal pay claims.
More than £4m has already been spent by local authorities, which still have to deal with about 32,000 claims, according to figures obtained by the Conservatives.
About 3500 new claims were made in the past 18 months, the figures show.
Margaret Mitchell, the party's local government spokeswoman, said: "It is quite simply not sustainable that Scotland's councils are continuing the scandal of spending such enormous sums of money delaying the legitimate settlement of equal pay claims.
"Local authorities should be facing up to this and negotiating a solution, not spending millions booting the matter into the long grass.
"It has been evident for many years now that this is an issue which must be addressed yet five years on there are more outstanding claims than settled ones.
"Quite simply, the issue of equal pay is still a ticking timebomb in Scotland's local authorities with some recording a significant increase in the number of claims made every year."
Claims still outstanding range from single figures in some councils to more than 8000 in Glasgow, the largest of Scotland's 32 local authorities.
Totals spent on legal fees and other associated costs range from nothing to six-figure sums, such as £184,759 in Edinburgh and £598,477 in Glasgow.