A Department of Home Affairs report has confirmed the office of former prime minister Scott Morrison instructed the public service to publicly reveal the interception of a suspected asylum seeker boat on election day.

The report prepared by Home Affairs Secretary Mike Pezzullo found uniformed Australian Border Force (ABF) and Australian Defence Force members, as well as public servants, acted with integrity by refusing a request to release a media statement while the operation was still unfolding.

A departmental statement was eventually issued minutes after Mr Morrison announced the interception in his final press conference as Prime Minister, but the report concluded officials refused requests to post it on social media or send it directly to journalists.

Home Affairs Minister Clare O'Neill says the election day episode was "disgraceful, shameful and characteristic of a national government which frequently pursued political interests above the national interest".

Mr Morrison held a press conference in his own electorate on May 21 where he was asked about reports an asylum seeker boat had been intercepted in the past few hours.

"Reports have just dropped now that a vessel has been intercepted in an attempt to illegally enter Australia from Sri Lanka. What's your response to that?" the journalist asked.

Mr Morrison confirmed that was the case, even though official confirmation from the department had not yet been made public.

"The information may have made its way to the journalist separate to, and before, the ABF newsroom announcement," the report said.

The statement and response from the prime minister on election day surprised many political observers, given the government's previous unwillingness to discuss "on-water matters".

The report also confirms public servants were pressured to act politically before that press conference, but refused.

Mr Pezzullo was aware the boat interception could be a political issue and, according to the report, told his staff to "keep an eye out for any chatter on social media or worse, any leaks to the media".

"It could become a very late election issue," he said.

With the operation still underway, the office of then-home affairs minister Karen Andrews directed Border Force to publish news of the interception.

The minister's office also requested the statement be emailed to selected journalists but according to the report, Mr Pezzullo refused.

"The release once cleared is to be posted to our news and media site – no more and no less," he said, according to the report.

The Liberal Party subsequently sent out text messages to thousands of voters, urging them to "Keep our borders secure by voting Liberal today".

The boatload of asylum seekers intercepted near Christmas Island was later returned to Sri Lanka.