A government MP has broken ranks to voice concerns about Australia’s $368 billion acquisition of nuclear submarines, calling for Parliament to do its job and debate the merits of the plan.

Fremantle MP Josh Wilson, whose electorate includes a major industrial shipyard, said he was not yet convinced the AUKUS submarine plan was the only way for Australia to provide for its security.

He said the deal raised questions about the disposal of nuclear material and cost of a plan to build subs from scratch.

“It should be a statement of the obvious to say that with an undertaking of this scale, complexity, cost and duration there remain considerable risks and uncertainty – that is the plain, hard reality,” Mr Wilson told the House of Representatives on Monday night.

“If we’re not able to have a mature and sensible conversation about those risks, there is very little chance we will manage them effectively.”

Mr Wilson said Opposition Leader Peter Dutton had made insinuations about his loyalty for inquiring about how the submarine deal would be treated under international laws governing the non-proliferation of nuclear material, when the deal was announced in 2021.

“For having the temerity to ask legitimate questions about those non-proliferation issues, the now Opposition Leader referred to me in this place as ‘Comrade Wilson’,” he said.

“It’s an irony that the Opposition Leader, for all his self-styled tough guy patriotism, appears to not the understand the fundamental difference between a liberal democracy and other systems in which asking perfectly reasonable questions is not only forbidden, but has dire consequences.”

The submarine plan’s price tag comes from two component parts: One to acquire Virginia-class submarines from the US, possibly from its own production line or second-hand from its fleet, and a second stage involving the joint Britain-Australia construction in Adelaide of a UK-designed submarine fitted with US weapons systems.

Mr Wilson said disposal of high-level nuclear waste, such as the byproduct of the submarines, was “a problem no country has solved”.

Only debate and scrutiny could resolve such questions, Mr Wilson said, while urging Parliament to play its role in a matter of national significance.

“The quality assurance mechanism in our system of governance and decision-making is contestability. We must always be able to have a rigorous and challenging conversation about defence and security matters,” he said.

“The AUKUS agreement, arrived at with some characteristically questionable secrecy by the former government, and some strange ministerial arrangements, is not a sports team of which we have all suddenly become life members.

“It is a significant partnership with two of our most important and closest allies, but it will only be effective if we do our job as parliamentarians, which is to look closely and ask questions in order to guard against risk.”

Former prime minister Paul Keating slammed AUKUS as the worst decision by any Labor government in a century last week and predicted that it would be opposed by the Labor Party’s rank and file membership.