A councillor wants West Midlands Fire Service to pay her £28,000 to work full time for her trade union.
Judy Foster, who is paid more than £51,000 in salary and allowances from various public sector roles, is employed as an administration officer by the fire service.
But for the past seven years the Labour councillor has been devoting all her working time to Unison, representing 280 fire workers.
The fire service has now insisted that Councillor Foster, who represents the Brockmoor and Pensnett ward of Dudley, spends half her working time on fire service duties and half with the union.
Fire bosses have offered to continue to provide half her salary and allow her to spend half the week with the union, which is dubbed "facilities time".
But Unison has appealed against the offer and says her union work should be full time and funded entirely by the taxpayer.
Tory councillors today reacted angrily to the demand and say the public should not have to pay "one brass tack" to the union.
Councillor Foster, who was elected in 1998, already picks up £9,300 in allowances from Dudley Council along with £14,475 as vice chairman of the West Midlands Police Authority.
With her £28,000 job, it brings her combined taxpayer-funded salary and allowances to more than £51,000.
Unison represents 280 staff in the West Midlands Fire Service while the Fire Brigades Union represents 2,000. The service employs 2,500 people.
Councillor Ken Turner, Conservative member for Dudley's Hayley Green and Cradley South ward, said: "If she wishes to represent the union, the union should pay the full amount. We should not be contributing one brass tack."
Conservative member for Harborne, Birmingham, Councillor John Alden said: "Given the dwindling number of Unison members in the fire service, we cannot justify paying for a full-time officer."
The fire service already gives Ms Foster time off in addition to her annual leave to carry out her duties as a councillor.
Councillor Foster said: "I only get 15 days off a year for my public duty role, the rest I do in my own time.
"Chief fire officers have all been supportive of the contribution I have made to the fire service.
"I had been on full time facilities time since 2003 until earlier this year.
"The fact that it is being raised now is politically motivated.
"We have appealed against the reduction because it would give me 50 per cent of the time to do 100 per cent of my union workload. It is not an unusual arrangement. A lot of councils give facilities time."
Unison regional organiser Mark New said he was "very disappointed" with the decision.
He added: "It is a normal arrangement for union activists in the workplace to be released from their duties to negotiate with employers. It is particularly important in this case where the fire service faces lots of changes due to cuts."