The training academy is expected to create thousands of jobs MPs are to urge the Ministry of Defence not to drop a planned £14bn defence training academy in south Wales.
The future of the proposed base at St Athan in the Vale of Glamorgan depends on the outcome of the Strategic Defence and Security Review (SDSR).
As submissions close, a group of Welsh MPs will meet Defence Secretary Nick Harvey later to press its case.
It comes as the Commons defence committee warns cuts could jeopardise armed forces’ current operations.
The plan for St Athan would centralise training for the armed forces in one location, but has led to controversy due to the closure of other bases in the UK.
Alun Cairns, Conservative MP for the Vale of Glamorgan, is warning that during lobbying so far too much attention has been paid to the economic benefits to Wales.
Mr Cairns said the campaign to bring defence training to Wales should also be pursued on military grounds.
He, with Rhondda Labour MP Chris Bryant and Welsh Secretary Cheryl Gillan, will meet Mr Harvey later to push for the programme to be approved.
“It has to be won because it is the best military thing to do”
Alun Cairns MP Conservative, Vale of Glamorgan
Mr Cairns said: “This is a meeting where we will be able to underline the military benefits of the defence technical college.
“Until now, there has been much focus on the economic benefits to the Vale of Glamorgan and to Wales but if we are to succeed, it has to be won because it is the best military thing to do.”
He said government finances meant it needed to see “value for money.”
“I believe that not only will this project provide the world class training our forces need and deserve but by bringing together the training of all three services, it could also could save the taxpayer £500m over 30 years,” added Mr Cairns.
Meanwhile, the Commons defence committee has said the SDSR was being pushed through so quickly mistakes were bound to be made.
It has warned that planned spending cuts for defence were so deep they could jeopardise the armed forces’ ability to maintain current military operations.
The SDSR is being carried out alongside the UK government’s overall comprehensive spending review, which is due to report next month.
Defence Secretary Liam Fox has assured MPs the SDSR would be a “real review” and not just a cost-cutting exercise.
Questioned in the Commons on Monday, Dr Fox was challenged to support the training academy by Cardiff West Labour MP Kevin Brennan.
“The whole of the defence training review and its consequences, including St Athan, will be looked at as part of the wider SDR,” he said.
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