RICHMOND'S Sydney Stack has pleaded guilty to breaching Western Australia's strict COVID-19 quarantine laws.

Stack appeared in Perth Magistrates Court on Wednesday where he entered a guilty plea to one count of failing to comply with a direction.

He will be sentenced on March 25.

The magistrate extended Stack's bail and ordered that pre-sentencing and psychiatric reports be obtained.

Stack and his manager Paul Peos declined to comment outside court.

Stack was granted bail earlier this month after spending almost three weeks, including the Christmas period, behind bars.

The 20-year-old was charged by police after being found out on the town in Northbridge during his compulsory self-isolation period, having entered WA from Victoria on a flight that stopped over in South Australia.

WA's border with SA was closed at the time after a recent coronavirus scare.

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Stack was granted approval to enter WA on compassionate grounds on December 10 for his grandfather's funeral.

He was issued with a direction to self-quarantine for 14 days at a nominated address in Northam, about 97km from Perth.

But he was found by police at 1.10am on December 19 in the party district of Northbridge.

It was also alleged he had been staying at a residence in Belmont and not at his nominated quarantine address.

The breach capped off a torrid year for Stack, who was overlooked in the 2018 NAB AFL Draft because of concerns about off-field issues but has since played 26 AFL games for Richmond.

He was handed a 10-match AFL ban and banished from Queensland in September for an incident outside of a Gold Coast strip club.

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Stack and Tigers teammate Callum Coleman-Jones broke the AFL's return-to-play protocols during that night out, which ended up with them being involved in a fight at about 3.30am. Richmond were subsequently fined $100,000.

The Tigers have promised to support Stack, who is out of contract at the end of the season, through his latest troubles.