Australia could become a “poison portal” for international radioactive waste under the Aukus deal, a parliamentary inquiry into nuclear safety legislation has heard.

New laws to establish a safety framework for Australia’s planned nuclear-powered submarines could also allow the U.S and UK to send waste here, while both of those countries are struggling to deal with their own waste, as no long-term, high-level waste facilities have been created.

The government introduced the Australian naval nuclear power safety bill in November last year. If passed, it will establish a nuclear safety watchdog, allow for naval nuclear propulsion facilities to be created, including for storing or disposing of radioactive waste from Aukus submarines. A second bill to enable the regulator to issue licenses was introduced at the same time.

Both have been referred to a Senate inquiry, which is due to report on 26 April.

The Australian Conservation Foundation’s Nuclear Free campaigner, Dave Sweeney, said the issue of waste disposal was “highly disturbing” and that the Aukus partners could see Australia as a “a little bit of a radioactive terra nullius”.

“Especially when it’s viewed in the context of the contested and still unresolved issue of domestic intermediate-level waste management, the clear failure of our Aukus partners to manage their own naval waste, the potential for this bill to be a poison portal to international waste and the failure of defence to effectively address existing waste streams, most noticeably PFAS,” he said.

The defence minister, Richard Marles, has previously accused the Greens of “fear mongering” when they raised similar concerns, saying the government would not accept waste from the other nations.

However, the legislation allows for the creation of facilities for “managing, storing or disposing of radioactive waste from an Aukus submarine”, and defines an Aukus submarine as either an Australian or a UK/U.S submarine, and “includes such a submarine that is not complete (for example, because it is being constructed or disposed of)”.

The Greens defence spokesperson, senator David Shoebridge said HMS Dreadnought, one of the UK’s first nuclear submarines had been “rusting away” since being decommissioned in 1980.

“You can go on Google Maps and look at them rusting away in real time, can’t you?” Shoebridge asked Australian Radiation Protection and Nuclear Safety Agency (Arpansa) chief regulatory officer, James Scott.

“Yes. There is no disposal pathway yet,” Scott said, adding he was “aware of the UK plans to establish a deep geological repository somewhere in the 2050s to 2060s”.

“There’s no exact date,” he said.

“The UK is pursuing a disposal pathway, and Australia will need to do the same. We are fully aware of this; we are engaging with our own radioactive waste agency, ARWA, on this, and it’s something that needs to be dealt with now, not later.”

The Dreadnought’s nuclear fuel has been removed to be stored safely. This has happened with some but not all of the submarines, but there is still no permanent disposal facility. The U.S also removes nuclear fuel for temporary storage.

Engineer Robin Townsend, a fellow at the UK-based Royal Institution of Naval Architects, told the inquiry that there was “a very big mountain to climb” to safely store nuclear waste, with the technology “still in its infancy”.

“All countries are struggling to not just decommission the submarines, but also … to deal with the waste. Planning is critical. People who say that you need to plan to store the waste for 100,000 years aren’t wide of the mark,” he said.

“There’s very little progress I think it’s fair to say …. I would strongly advise that you do take it into account as early as possible.”

Other concerns raised at the hearings include a lack of transparency with the Aukus deal and the independence of the watchdog. There is another public hearing on Thursday.

The defence department said the bill would provide “a regulatory framework able to accommodate any future government decisions regarding the management of radioactive waste”.

“It would not determine those future government decisions, nor does it presuppose them,” it said in a statement.

Under questioning from Shoebridge, the defence department’s domestic nuclear policy branch assistant director general, Kim Moy, said nuclear facilities, including high-level waste facilities, could be established but that they would be established under regulations, which can be disallowed by parliaments.

Asked if such facilities could take waste from Australian, U.S, or UK nuclear-powered submarines, Moy said: “Yes. The bill enables the management of radioactive waste. It is a separate question about what policy or plans are associated with those aspects, said Moy.