Plaid Cymru's vice-president has questioned whether the party should support a new military training academy at St Athan in the Vale of Glamorgan.
An artist's impression of how the military academy would look
MEP Jill Evans, who also chairs CND Cymru, said the proposed 5,000-job centre was inconsistent with the spirit of the party's defence policy.
BBC Wales has obtained a copy of her paper for the party's ruling national council in Aberystwyth on Saturday.
But Vale Labour MP John Smith said her comments were "dangerous nonsense".
In the document leaked to BBC Wales' Dragon's Eye programme, Ms Evans also said that if Wales were to become independent, it should slash spending on defence and pull out of Nato.
She said Plaid - which has a long-standing tradition of pacifism, although it is not a pacifist party - should condemn what she said was the increasing militarisation of Wales.
Her paper suggested that Plaid should be committed to purely defensive armaments, with existing military infrastructure under Welsh control with a chain of command answerable to a future Welsh Parliament.
Plaid has been in coalition with Labour in the assembly government since last May.
The MEP also called on the assembly government to investigate any links between the private companies involved in St Athan and the international arms trade.
Her view was backed by Anna Jane Evans, a Plaid member and a member of Arfon Peace Group, who told BBC Radio Wales the party and Wales' peace groups had been "caught napping" over the creation of the St Athan centre.
Jill Evans has been a Plaid Cymru MEP since June 1999
Anna Jane Evans said: "This has come under the carpet without any debate within the Welsh assembly.
"It think it [St Athan] should be stopped until we have a full explanation of who the investors are, what their priorities are, who they're answerable to and who is going to be trained there."
Mr Smith called Jill Evans's views "simply unacceptable" and her comments "dangerous and irresponsible nonsense that should be stopped now".
He said: "I call on those who stimulated this debate with this paper to do just that very quickly. We want these jobs for Wales."
He added: "The idea that we didn't have a debate is also absurd. It took us two-and-and half years of hard, all-party, campaigning to get this to Wales. It was politics at the best.
"Every senior politician I approached to ask for help, including Plaid Cymru politicians, supported me on this."
Building work on the St Athan centre is due to start in 2009, with the final phase expected to be completed by 2013.
Conservative AM Alun Cairns said he was "staggered" by Jill Evans's "naivety".
He said: "I doubt very much whether Jill Evans's own leader, Deputy First Minister Ieuan Wyn Jones, agrees with her view.
Logistics and personnel
"Her comments send out all the wrong signals to the UK government and developers."
Plaid has declined to comment until the party's national council meeting has taken place, stating it does not wish to discuss a leaked document.
It is unclear whether the party's national council will have an opportunity to vote on the resolutions contained in Jill Evans's paper.
According to the party, that will be a decision for the chair of the council.
The Ministry of Defence has confirmed it will go ahead at the site with the training academy part of the plan, known as Package 1, but doubts remain whether other training, such as security, will also be carried out there.
The MoD said in October that it was still negotiating the second section, or Package 2, providing training for logistics and personnel staff, security, intelligence and photography at the site.
The two packages are worth a combined £16bn and up to 5,000 permanent jobs, although most would come with the first phase of the academy.