Metrolink tram drivers in Greater Manchester are set to vote whether to strike next month in a dispute over pay.
Unite said its members had been offered a pay increase of 0.3% for January to March 2020, followed by 0.7% from April 2021 to April 2022.
The union has branded the 1% increase for a 15-month period as 'derisory' and would amount to a 'hefty real terms pay cut for workers'.
Unite added that the tram network in Greater Manchester could grind to a halt because of the planned action.
In a statement, the union said it has been in pay talks with Metrolink since February and, with negotiations now "exhausted", the union has "no option" but to begin balloting for strike action.
The strike ballot opens on Thursday, August 26, and closes on Friday, September 10.
If workers vote for strike action then strikes could begin before the end of next month.
The union represents over 300 drivers and supervisors at Metrolink.
Unite regional officer Dave Roberts said: "Unite has had no option but to ballot its members for strike action after Metrolink refused to make an acceptable pay offer despite six months of talks.
"Our members have gone beyond the call of duty to continue to operate throughout the pandemic and to be offered a derisory pay offer, a deep pay cut in real terms, is deplorable.
"If workers vote for strike action then Greater Manchester will effectively grind to a halt, affecting both commuters and those hoping to attend sport and leisure events.
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"Our workers are reluctantly balloting for industrial action as a last resort, but Metrolink could still avoid strike action occurring by returning to negotiations and tabling a realistic pay offer."
Transport for Greater Manchester has been contacted for a comment.
Rob Cox, director of service delivery for the operator KeolisAmey Metrolink, said: "Our drivers have worked extremely hard throughout the pandemic and provided vital services for key workers during uncertain times.
"Now, our focus must shift to supporting the recovery of Metrolink as we emerge from the pandemic. The Metrolink service is funded by the general public and we have a duty to make sure that the cost of operating the network does not become unaffordable.
"Whilst Unite are disappointed with our offer, we believe that it is a fair proposal which gives certainty to our drivers into 2022 and avoids the need to make any significant changes to their terms and conditions.
"We remain available to discuss any reasonable counterproposal that Unite bring to the table."
