Christopher Pyne's Twitter account in porn mishap

Australian Conservatives senator Cory Bernardi and Opposition Leader Bill Shorten have expressed concern about the implications of any breach for national security given the highly sensitive nature of Mr Pyne's ministerial portfolio.

There were also attempts to breach the Defence Industry Minister's Facebook account on Wednesday, a spokesman said, denying that the disturbance raised broader concerns.

Mr Pyne's account "liked" a raunchy video from account "XxxPornGay" in the early hours of Thursday morning as people across the country were celebrating the result of the same-sex marriage postal survey.

"I was hacked overnight! I was [sleeping] at 2am. Someone tried to hack my social media yesterday. Maybe they are making mischief over the plebiscite?" Mr Pyne tweeted later in the morning.

On the platform's mobile application, a post can be liked easily as people scroll through their timeline or an individual account, requiring only an inadvertent tap with a finger.

The act by Mr Pyne's account was picked up by a Twitter bot that keeps track of politicians' activity on the platform.

Ordinarily, the Minister's staffers are probably the only other people with access to his account.

Senator Bernardi called for an investigation, saying he was concerned "Australia's national security may have been placed in a compromising position".

He has drawn up a motion for the Senate to express its "grave concern that a social media account, passwords and potentially the internet-enabled device or devices of the Minister for Defence Industries, Mr Christopher Pyne, may have been hacked".

Senator Bernardi's motion calls on Attorney-General George Brandis to investigate the incident and report back to the Parliament.

Mr Shorten said the government needed to take seriously the possibility of a security breach because of Mr Pyne's work with "national secrets".

"When any minister, especially a defence minister, has their accounts hacked, I do think this deserves serious investigation," he said.

The Opposition Leader said Labor would consider Senator Bernardi's proposal when it is considered in the next parliamentary sitting period.

It remains unclear why a hacker would use access to a government minister's social media account exclusively to like a single pornographic post in the dead of night.

A spokesman for Mr Pyne said: "The account in question was a public online social media account, not a Defence, government or parliamentary social media account. There are no defence or national security implications."

"It's a salutatory reminder to all of us that not everyone out there wishes us good will, to routinely change passwords and to be mindful of cyber security," he told Fairfax Media, saying appropriate action had been taken.

"The minister's office was alerted by Facebook yesterday that there were attempts to breach his Facebook account."

Earlier this year, the account of suspended Australian Border Force commissioner Roman Quaedvlieg liked an erotic clip with the caption, "I think your c-ck likes me!".

Last year, the account of Treasurer Scott Morrison liked a post concerning China's human rights record. He subsequently blamed hackers.

In 2014, the account of Foreign Minister Julie Bishop was compromised and tweeted phrases like "lmao you gotta read this, its epic" and "haha this blog by you is crazy".

Cyber-security adviser Rachael Falk??? said the incident was a timely reminder for people to protect their online accounts.

"Always use a good, strong, difficult-to-guess password and switch on two-factor authentication," she said.

Two-factor authentication, an extra layer of security available on many platforms including Twitter, requires a user to provide a second piece of unique information when logging in. This is usually a code sent to a mobile phone or app.

- with James Massola