The majority of members of Unite the union have rejected the 2.75% pay offer.
Unite called the offer 'unrealistic and insulting,' pointing out it amounts to just £1.83 a day.
The MJ understands that the other two local government unions are likely to accept the 2.75% offer, which will mean it can be implemented.
Unite said it would be pressing for local pay deals after 70% of its members rejected the offer.
National officer for local government at Unite, Jim Kennedy, said: 'Our members are right to reject poverty pay and we will be stepping up the campaign for a fair wage that properly respects the contribution these workers make to our society in delivering services from the cradle-to-the grave.'