London Underground workers are set to cast their vote on whether to take strike action over pay.
The Rail, Maritime and Transport union (RMT) said it was unhappy at the latest pay offer from London Underground.
It also criticised the freezing of pay bands, which it said would create a two-tier workforce.
Transport for London (TfL), which runs London Underground, said it encouraged RMT to "continue to engage with us" and "put our offer to their members".
It said it had offered staff a 5% pay increase for 2023 and that some roles on the Tube attracted a pay range which had been frozen for this year. It added this impacted "less than 2% of London Underground colleagues".
But RMT general secretary Mick Lynch said: "Tube workers who help bring vast amounts of value to the London economy are not going to put up with senior managers and commissioners raking it in, while they are given modest below inflation offers.
"The refusal of Transport for London (TfL) not to restore staff travel facilities and create a two-tier workforce is also unacceptable."
The ballot closes on 19 December.
Last month, the union called off strike action following a row over 600 post closures.
TfL is trying to make about £230m of savings as part of a government funding deal which was agreed in August 2022.
The transport authority has received six bailouts from the government after its revenues plummeted in the pandemic.