Defence chiefs have rejected criticism of plans to reform armed forces pension schemes.

The Ministry of Defence claimed on Tuesday that its plans to modernise pension arrangements had been misrepresented and would benefit many current and ex-service personnel.

Under the Armed Forces Bill announced in the Queen's Speech, the age at which veterans would start to receive pensions would be extended from 60 to 65.

Defence minister Ivor Caplin said his department would respond to a critical report by MPs before the bill goes before the Commons in the New Year.

The move is aimed at offsetting the estimated £125 million increase in costs to the Ministry of Defence of the pension schemes, caused by the increased life expectancy of ex-services personnel.

The MoD argued that its changes would simply bring pension arrangements in line with many current practices in the private sector.

Officials rejected claims that members of the current scheme would be compelled to join a new scheme. It would in fact only cover new entrants from 2005.

The scheme will also remain as a final salary scheme at a time when many private firms are moving to different arrangements.

Widows would see a four-fold increase in provision and long term partners - including same-sex relationships - would be covered by pensions provisions.

"It could have been an awful lot worse. We have listened to individuals and we have consulted," said an MoD spokesman.

"The Armed Services are in a unique position. They could be killed and maimed. We wanted to offer a pension scheme that reflected that fact."

But in their report published on Tuesday, the Commons defence select committee described such a move as "arbitrary and unfair", saying that most recipients would be worse off as a result.

"Most personnel will have to wait an extra five years before receiving their pension, and early departure benefits will be of lower value," said committee chairman Bruce George.

"The overall value of benefits for those who transfer to the new pension schemes will be less than those who remain on the existing one.

"Our armed forces make a unique contribution to this country and they deserve better than this."

The report criticised the delays in publishing the review of armed forces pensions, which began in 1997, and argued that it had been "hamstrung" by considering only those new schemes which cost the same as existing ones.

"We have always been unhappy that the government in its review of armed forces pensions has imposed on itself the constraint of how much current benefits cost, rather than looking more generally at what armed forces personnel deserve," said the report.

"We are even less happy now that it emerges that the government proposes to reduce the overall value of benefits under the new scheme, compared with the existing scheme.

"The goalposts of 'cost neutrality' have been shifted to the disadvantage of future personnel."

Ministers also came under fire over proposals to change the compensation scheme, so that the burden of proving whether or not an illness or disability was caused by active service shifts from government to claimant.

"Because of the special risks that armed forces personnel are required to run, and because they are likely to be involved in situations of great uncertainty, with uncertain effects on their health, we continue to believe that the onus should remain on the government to prove that service was not responsible for causing or worsening a condition for which a compensation claim is made," added the report.

MPs also called on the government to act more swiftly in compensating those veterans whose pension schemes were wrongly taxed, but praised planned improvements in the entitlements for widows or widowers of those who die in service.

The Royal British Legion, which represents veterans, welcomed the committee's report and called on ministers to reconsider proposed changes that would make it more difficult for ex-service personnel to claim a war pension.

"The Legion is most concerned over the government's declared intention to change the standard of proof of entitlement to a war pension from 'beyond reasonable doubt' to 'on the balance of probabilities'," said a spokesman.

"To move the goal posts in this way will deprive members of the armed forces of a much-prized recognition of their service to the country."