Attorney-General Christian Porter has claimed that there is a legal loophole in the recent medivac legislation that could prevent the Government from returning asylum seekers to offshore detention after they receive medical treatment in Australia.

This comes after Defence Minister and Speaker of the House Christopher Pyne warned that the then bill would jeopardise Australia’s border security. The passing of the bill was a historic loss for the Coalition Government as they were defeated by the combined votes of Labor, the Greens and crossbench MPs.

Mr Porter has said that new legal advice has shown that the legislation was poorly drafted and contains loopholes. He has said that one amendment in the legislation had failed to be linked to the appropriate section the Migration Act governing the ability to send treated asylum seekers back to offshore detention facilities.

Mr Porter said that legislation was “terrible” and that “this legal loophole is significant,”

He said that the loophole robbed the Government of “lawful authority to send them (asylum seekers) back.”

Mr Porter expressed regret that the Government did not have the political capital on the floor of Parliament to change the legislation “in the best interests of the Australian people,”

However, Mr Porter said that the legal advice he had cited would not be fully released, claiming that it could potentially be used against the Government in litigation. He said that the Government would use “ever power under our auspices” to make sure asylum seekers are returned to offshore detention.

Labor denies that there are any loopholes in the legislation and has called on the Government to publish the legal advice they obtained.

Shadow Attorney-General Mark Dreyfus said that Labor believed “there is no difference between Labor and Liberal border protection” and that the warning of a loophole was “desperation”.