Tony Abbott has accused Labor of attacking Australia’s way of life by proposing a public vote on whether to become a republic.

The former prime minister says the republic vote is the federal opposition’s latest attack after it vowed to legalise same-sex marriage with a parliamentary vote.

The proposed republic vote would cost the same $150m as a plebiscite on same-sex marriage and would not answer the question of whether a president should be elected by voters or chosen by the government, he said.

It could undermine the legitimacy of Australia’s system of government without putting anything in its place, he warned.

“This attack on the monarchy is just the latest instalment in the green-left’s war on our way of life that Shorten Labor has largely made its own,” he writes in the Australian on Wednesday.

Abbott accused Labor of trying to divide and diminish the nation with its “envy-exploiting” campaign against inequality.

He also appeared to take a swipe at his own side.

“The argument that ‘the government should be re-elected because the alternative is worse’ is not normally compelling but, thanks to Shorten’s latest ploy, it has become a lot more powerful.”