Matildas centre-back Clare Polkinghorne will leave Brisbane Roar ahead of the W-League finals to join Swedish top-tier outfit Vittsjo GIK.

The Roar are second on the table and all but confirmed to play finals, given their outstanding goal difference.

But they will have to push for their first championship in 10 years without club captain Polkinghorne, who has been released from her contract and will depart after Brisbane's final regular-season game, against Newcastle on March 28.

"An opportunity came up in Sweden and the club has been really supportive in me pursuing that opportunity," Polkinghorne said.

"Obviously the timing of it all is disappointing for me, but it's an opportunity I need to take to ensure that I'm playing regular football at a high standard throughout the year and preparing in the best possible environment for the Olympics.

"Right from the start the club has been very accommodating and it helps that we have had open communication throughout the whole process."

Brisbane are the second team this season to lose their captain to a Swedish club, after Adelaide sold skipper Dylan Holmes to BK Hachen earlier this month.

Polkinghorne's Brisbane and Matildas teammate Emily Gielnik played at Vittsjo last season.

A two-time Julie Dolan Medallist, Polkinghorne recently played her 151st W-League game for the Roar.

"I don't think it's ever going to be matched, to stay at one club and be as successful as she has been, winning trophies and personal accolades and playing 150 games," coach Jake Goodship said.

"She basically symbolises what Brisbane Roar stands for.

"As hard as it is losing Clare, she has done the utmost work behind the scenes to ensure the confidence is high in the players stepping up to fill her shoes."