Minister for Defence Simon Coveney has been urged to review plans that will force hundreds of soldiers to leave the army over the coming years.

Speaking on RTÉ's This Week, Minister of State at the Department of Agriculture Ann Phelan said she has "grave concern" over a measure which will see soldiers below the rank of sergeant forced to retire after 21 years service.

The measure applies to all privates and corporals who joined since 1994.

The first batch of soldiers to be affected by the rule will have to leave the army next year.

Around 400 troops will be forced out over the coming five years under the measure.

She has called on Simon Coveney to give the soldiers "a second chance" and to allow the troops the flexibility to remain on after the 21 years expires.

This will give them a chance to obtain a higher rank or to re-train, she said.

Ms Phelan said she was concerned over the fact that most of the soldiers leaving under the rule were aged around 39 or 40.

She said that they have young families, mortgages and other debt. 

Minister Phelan said it was of concern that these soldiers cannot draw down their pensions for more than a decade in most cases.

'No brainer' to allow troops to remain - Penrose

Her Labour party colleague, Longford-Westmeath TD Willie Penrose, also called on Minister Coveney to allow the soldiers to remain on until they are aged 50, past the 21 year limit. 

The current rule would force out some of the most experienced soldiers.

These soldiers have done several tours of duty with the UN and EU overseas, he said.

Speaking on the same programme, Deputy Penrose said it was a "no brainer" to allow the troops to remain, subject to the existing fitness tests which they already have to pass.

Soldiers' representative body PDFORRA also called on the Government to allow the affected soldiers to remain on past the 21 year limit, until their 50th birthday.

Secretary General Gerry Rooney said that soldiers already had to pass fitness tests to remain in the army.

He said the post-1994 rule was agreed at a time when fitness levels were "incomparable" to the high level demanded of and achieved by members of the Defence Force today.

The current batch of troops affected by the measure were among the fittest ever produced and who had given distinguished service at home and overseas, Mr Rooney said.

Discussions 'confidential' - Department of Defence

A spokesman for the Department of Defence said that the issue was the subject of a formal conciliation claim by PDFORRA and that the terms of the discussions arising from this were confidential. 

However, the spokesman said that the rules had been updated and agreed with PDFORRA as recently as 2006 and it was not the case that this measure could be a surprise to the affected soldiers.

According to a briefing note on the discussions seen by This Week, the department has proposed lowering to 15 years the maximum period which privates can serve in the defence forces.

The Department also proposed allowing some technical-grade troops to remain in service longer than non-technical grades. 

However there has been no agreement on the proposals.