Council employers have offered an improved 'final' pay offer to staff but have offered council chief executives and chief officers a lower increase.
The national employers, who negotiate pay on behalf of 350 local authorities in England, Wales and Northern Ireland, have increased their 1.5% offer to 1.75% for the majority of employees, with those on the lowest salaries receiving 2.75%.
However, senior councillors have only offered 1.5% to council bosses.
Honorary secretary of the Association of Local Authority Chief Eexecutives (ALACE), Ian Miller, said of the offer: 'We are disappointed that it does not match ALACE's simple request for equality of treatment with the generality of local government staff.
'The employers have given no reasons for valuing the work and contribution of the most senior officers differently from other staff.
'We will seek an explanation from the employers about why they are proposing to depart from arrangements that have been applied since 2016 and which have delivered equal treatment.
'In the meantime, we are not in a position to accept the offer that has been made.'
The latest pay offer to staff equates to a £328m increase to the national pay bill for local government.
However, one senior council officer said the 3% pay increase offered to NHS staff had ‘blown a hole in the local government employers' strategy'.
They said: ‘This widens the gap in pay between social care and NHS staff.'
Unison, GMB and Unite had been calling for a 10% pay rise but employers' secretary Naomi Cooke wrote in a letter to councils: 'The national employers, who are all senior elected members drawn from councils across England, Wales and Northern Ireland, are acutely aware of the added impact that the pandemic is having on councils' budgets and future financial stability.
'This is why their improved offer is final; it represents the limit of affordability for most councils.'
But Unison's deputy head of local government, Mike Short, said the 0.25% increase on the initial offer was 'insignificant' and said employers were 'failing to recognise' workers' efforts.
GMB national secretary Rehana Azam described the offer as 'woeful' as she backed the idea of industrial action.
Unite national officer Jim Kennedy added: 'Local government employers are guilty of rank hypocrisy.
'On the one hand, they say they recognise the critical work that our members have undertaken, especially during the pandemic, and, on the other, they are intent on imposing a real-terms pay cut on workers.
'If the employers have any conscience whatsoever they will not be able to sleep at night after making such a miserable, morale-destroying pay offer.'
