Nearly 100 civil service jobs could be lost in Dundee and Fife after HM Revenue and Customs announced plans to cut staff.
HMRC said 150 staff across Scotland are being targeted for voluntary redundancy.
A spokesman said the cuts are necessary because a greater amount of HMRC business is now conducted online, but stressed there is no immediate threat of compulsory redundancies.
However, the Public and Commercial Services Union (PCS) condemned the proposal and said the cuts which would include staff in Dundee responsible for recovering debts owed to the taxman as “counter-productive in the extreme”.
Staff at HMRC in Scotland were given offers of voluntary redundancy on Wednesday. Some 80 staff based at Saltire House in Glenrothes responsible for carrying out tax assessments have been offered terms, as have 50 in Irvine, around 15 in Dundee and an unspecified number in Inverness.
Around 250 staff based in Northern Ireland and 80 in Plymouth were also offered “targeted voluntary exits” this week.
Hamish Drummond, secretary of the Scotland East branch of the PCS, said the decision to scrap 15 positions based in Caledonian House in Dundee makes little sense.
He claimed the Dundee staff affected by the proposals are responsible for chasing up debts owed to HMRC and that without them the work would need to be carried out by an outside debt collection agency, which would cost the taxpayer more money.
“We are utterly opposed to these cuts at a time when there is £123 billion identified unpaid tax each year that is not going into the Exchequer,” he said.
“Cutting the jobs of people working to bring that in is counter-productive in the extreme.”
Mr Drummond added: “There is already too much work for the HMRC in Dundee and work will now have to be outsourced. They will be paying a private collection agency instead.”
Although HMRC has said there is no plan for compulsory redundancies or to close offices, Mr Drummond said staff are now beginning to worry about their jobs.
“There is definitely a fear that their position will change down the line,” he said.
He added: “The staff in Dundee will all be earning somewhere in the region of £19,000 a year. Together that is something like £280,000 that will be taken out of the local economy.”
A spokesman for HMRC said the organisation would try to find alternative roles within the organisation if they refuse to accept voluntary redundancy.
He added: “An increasing number of customers are choosing to do business with us through our online services, which has reduced our need for physical sites.
“This change has seen the nature of our work shift away from the mass processing work of the past to the more specialist, but less labour-intensive, roles required in effective policing of the tax system.
“As a result, some areas of our work do not require as many staff, so we are offering targeted voluntary exits to staff in Glenrothes, Irvine, Dundee and Inverness.”