Australia’s leading prosecutors have accused the Department of Home Affairs of making a decision that could let criminals escape punishment by leaving the country, in a letter sent to department secretary Mike Pezzullo.

The letter was signed by the Director of Public Prosecutions (DPP) in each of Australia’s states and territories, according to The Herald Sun.

Visa cancellations on character grounds under section 501 of the Migration Act have captured public attention, especially in light of the high numbers of New Zealanders being deported. Character-based visa cancellations usually follow a criminal conviction.

But there is an increasing trend where visas are cancelled before a trial takes place. That is possible under a different provision – section 116 – that allows the government to cancel a person’s visa when they are charged with a crime, before they are ever tried, convicted or sentenced.

The Migration Act lets the states and territories issue "criminal justice stay certificates", which is supposed to hit pause on any plans to deport someone who hasn’t finished their criminal justice process. But the DPPs said they had been told home affairs had decided that the certificate could be trumped by a separate section, section 198, compelling the government to deport “an unlawful non-citizen” who asks to be removed. That section says the deportation has to happen as soon as possible.

The department’s decision could have “far-reaching” consequences, the DPPs wrote. They cautioned that it meant “a non-citizen could circumvent the administration of justice – at any stage of that process – simply by requesting their removal” from Australia.

The DPPs suggested the decision could invite criminal tourism — people travelling to Australia “for the specific purpose of carrying out criminal offences, knowing that they would be effectively rendered immune from prosecution and the consequences of conviction by making a request for removal”.

It is not clear whether any criminal defendants have yet been deported before being convicted or sentenced. BuzzFeed News has approached each DPP for comment. At the time of publication, the DPPs in Queensland, South Australia and Victoria had declined to comment.

Shadow attorney-general Mark Dreyfus criticised the government’s decision in an interview on ABC radio today, saying that “we’ve got to have trials taking place when people have committed offences here in Australia”.

“I think that the administration of our criminal justice system, making sure that people who’ve committed serious crimes in our country are ... charged and convicted and punished for their crimes, has got to take precedence over any idea [home affairs minister] Mr Dutton and his department may have.”

In the letter, the DPPs foreshadowed a potential legal challenge, writing that they “trust your department will change its view, to obviate the necessity of any challenge to that view.”

In an emailed statement, the Department of Home Affairs confirmed that Pezzullo had received the letter, but did not respond to questions about his response, or whether anyone had been deported ahead of a trial.