Wakefield Council sent letters to thousands of workers before Christmas offering compensation for years of unequal pay.
Some workers would receive £6,500. But Unison regional officer Chris Jenkinson said, “I suspect the council’s objective is to get as many people as possible to sign up for what is an inadequate offer.
“Coming at this time, the undoubted financial pressures that Christmas brings provide a definite incentive to accept.
“But our advice to members is to reject the offer. It amounts to somewhere in the region of 20 to 25 percent of the value of their claims and therefore considerably undervalues what they are entitled to.
“We are advising that they pursue an official grievance based on the fact that they have been discriminated against because the pay system is inherently biased against women.
“We want them to reject the offer and allow the union to pursue their claims through the courts.”
The council said the timing of the letters was irrelevant.