Malcolm Turnbull has criticised Labor’s plan to reintroduce an emissions trading scheme, warning it would be a “jobs-destroying” measure, a handbrake on the economy, lead to “much higher energy prices” and do little to combat climate change.

The prime minister also denied accusations that his decision to sign a contract guaranteeing that 12 submarines would be built in South Australia was a consequence of an agreement he made with federal MP for SA Christopher Pyne and senator Simon Birmingham in exchange for their support when he challenged Tony Abbott for the leadership.

“I’m not going to go into the ins and outs of the change of leadership,” he said.

Speaking on ABC radio in Adelaide on Wednesday, Turnbull said the $50bn submarines deal his government has struck with French company DCNS would be signed by the end of the year.

The deal would allow for all the submarines to be built in Australia, rather than overseas. While it was a more expensive option, it was important for local jobs, he said.

“The difference between the cost of building all the submarines in France and all the submarines in Australia ... is a very manageable one,” he said. “It’s not the huge figure that people have speculated about.

“It is [also] critically important that with a sovereign defence capability we have the skills in Australia to build it, to maintain it, to sustain it. It is important that it is built in Australia ... as a matter of national security.”

He denied speculation he was keen to sign such a contract to hold up his end of a deal with his South Australian colleagues.

“I honestly think you’re trying to turn a great opportunity ... for Adelaide and South Australia into a debate about politics,” he said.

Abbott had pushed strongly for the submarines contract to be awarded to Japan ahead of France when he was in office.

After the French-won submarines contract was announced on Tuesday, Abbott sent a letter to Japan’s prime minister, Shinzo Abe, thanking him for trying to win the contract, according to reports.

On climate change policy, Turnbull said Labor’s new proposal to introduce two emissions trading schemes if it wins the election would “double the burden” on Australia relative to other countries.

The first scheme, for big industrial polluters, would force power generators to pay for the closure of a competitor’s dirty brown-coal-fired plant, while the second scheme, an electricity industry-specific “intensity based” trading scheme, is similar to one once backed by Turnbull himself.

Labor says the policy would minimise the hit on household power bills but it has left important details to be determined after the election.

Turnbull said the Coalition already had a strong climate change policy and he criticised Labor for wanting to run too far ahead of the rest of the world.

“We agreed with the rest of the global community on emissions reduction targets by 2030 ... our commitment is very substantial – it’s to reduce our emissions by 26-28% on a per-capita basis,” he said.



“Labor is proposing nearly twice as much: 45%. That is well above what we committed to at Paris and will put a very big burden on Australians.

“What they’re proposing is to double the burden on Australia, relative to other countries ... When a similar target was modelled on the basis of Labor’s previous scheme, it would have required a very substantial increase in electricity prices.”

Turnbull then warned the rest of the world would not be inspired to follow Labor’s lead.

“The key thing with climate change is to ensure that you get global action and so if one country decides to – just say there’s a change of government and they double their particular cut in emissions – that’s not going to motivate others to do any more,” he said. “Others will just say thanks very much.”

At a later press conference, Turnbull again attacked Labor’s plan for its likely economic consequences. “This is yet another economic handbrake that Labor is putting on our economy, another restraint on jobs to add to all the other job-destroying measures they’re proposing,” he said.

The Labor leader, Bill Shorten, said unlike the Coalition, Labor accepts climate science and is prepared to avoid the high costs of inaction.

“We do not consider climate change a question of ‘belief’, we know it is an economic and environmental reality ... The cost of inaction, to our economy and the environment, will be profound. This is not a price Labor is prepared to make the next generation of Australians pay,” Shorten said.