The union has previously held strike action over expected job cuts
|
HM Revenue and Customs plans to cut 1,000 jobs in Wales by 2010, a union has claimed.
The Public and Commercial Services Union (PCS) said the losses would be in addition to 6,000 public sector jobs in Wales already under threat.
A spokesman for HM Revenue and Customs said investment in IT systems and call centre upgrades would result in a "smaller workforce" and fewer offices.
The PCS is meeting next week to discuss strike action.
Chris Hopson, communications director of Revenue and Customs, said the service was announcing an investment of £500m per year for next five years.
"There will be an impact on our staff," he said.
"You can't make that kind of investment without running an efficient and effective organisation.
"So yes, we will have a smaller workforce and we will have a smaller network of offices, but the reason we're doing it is because we want to improve the service to our customers."
Mark Serwotka, general secretary of PCS, described the comments as "nonsense" and the proposals as "a political target set by the chancellor to cut 100,000 jobs in the civil services".
'Devastating'
The union predicts up to 200 HM Revenue and Customs offices would close across Britain, with many of those in Wales in economically deprived areas.
Mr Serwotka said the claim of 1,000 job losses in Wales was a "conservative estimate" based on the current number of staff, the offices likely to be closed and figures given by management to staff.
He said: "It would be devastating for the valleys and parts of north and west Wales in terms of public sector employment.
"But also people who at the moment take for granted that they can go and see a trained civil servant face-to-face, will now find that the public service had gone."
A spokeswoman for HM Customs and Revenue later added that the service would consult with its "customers" to "find out what they want from us".