Unions and management at An Post have clashed over the number of redundancies likely to result from the closure of the company's loss-making parcel and courier service SDS.

The company yesterday announced that 270 of the 450 staff at SDS would lose their jobs with the remainder transferring to other positions within An Post.

However, the Communication Workers Union (CWU) said it was seeking information on what was going to happen to 400 other staff involved in providing the SDS service, including both the remaining company staff and other An Post staff who work for the parcels company.

Mr Steve Fitzpatrick, the new general secretary of the CWU, said the company was wrong to state that only 450 would be affected by the closure of SDS. "There are hundreds of other people who in full or in part provide the SDS service - what are they going to do now?" he asked.

An Post said it would continue in the parcels business but this would be done via the main An Post group. It strongly denied that approximately 400 staff were dependent on SDS for their weekly workload.

The company said while it was taking radical action to address the losses at SDS - believed to total €20 million in the last two years alone - it still needed to cut another 1,450 jobs as part of a more widespread change programme.

Chief executive Mr Donal Curtin said the company remained on a "knife-edge" and if the redundancies were not delivered the consequences could be very serious. He said while the recent elections and referendum provided a small boost to the company, a price rise was still needed and An Post had to cut its ties with loss-making subsidiaries. An Post had already ended its involvement with one small business, Wizard Direct Stationery, he said.

He said SDS "never made money" and had become a serious drain on the company. Efforts to sell it had failed, with only one company - believed to be DHL - taking any sustained interest.

Meanwhile, it has emerged that the general secretary of the Irish Congress of Trade Unions (ICTU), Mr David Begg, has written in recent weeks to the Minister for Communications, Mr Dermot Ahern, about the situation in An Post and SDS.

In a letter dated July 2nd Mr Beggs warned that closing SDS could be "very damaging to the partnership process".

He also indicated he had no wish to clash with Mr Ahern, but cautioned the Minister to be wary in how he approached the issue.

"I am anxious to avoid another crisis in An Post, if possible," he wrote.