In a statement released last night, Australia Post said most jobs would be shed from the company's Melbourne headquarters.

``While the impact in other states and centres will be small, details are still to be worked through,'' Australia Post said.

The Communications, Electrical and Plumbing Union said there was very little room for reducing the company's Tasmanian workforce.

``Our view of Australia Post in Tasmania is that the organisation has already been cut to the bone,'' CEPU state secretary Trevor Gauld said.

``Our union will be vehemently opposed to any sort of downsizing.''

Mr Gauld said Australia Post had not yet ruled Tasmanian job losses in or out, with the union expected to find out the fate of the state's workers this morning.

``If there are any further cuts to jobs to Australia Post in Tasmania, the community's level of service from Australia Post would suffer dramatically,'' Mr Gauld said.

Australia Post said the cuts would most affect those with managerial, administrative and support roles.

The company said posties and retail staff would escape the cuts unscathed, and no post offices would close.

Chief executive Ahmed Fahour said the job losses came after a dramatic decline in Australia Post's letters service.

He said the volume of letters dropped by about 30 per cent over the past five years, with the decline expected to accelerate in coming years.

Mr Fahour confirmed the company was lobbying the federal government to relax regulations tying the company to delivering standard mail five days a week.

``Without postal services reform the losses in our letters business will reach $1 billion per annum within a few years,'' Mr Fahour said.

``We have to continue to reform our business, and we need support from the community and the government in terms of regulatory change.''

However, Mr Gauld renewed calls for the federal government to reject any scaling back of the weekday mail delivery system.

He said Australia Post had an obligation to Australians to continue providing the service.