Sydney FC shareholder Anthony LaPaglia has doused rumours he could leave the A-League club, throwing his support behind new coach John Kosmina.

The Hollywood actor reportedly threatened to stand down from the board and sell his 7.5 per cent stake in the club after he was not consulted about the move to sack coach Branko Culina two weeks ago.

Sydney chairman Andrew Kemeny admitted LaPaglia had some "issues" with being left out of the decision but was confident the matter had been resolved.

The Without a Trace star has now confirmed all is well, giving Kosmina, who has started his reign with two wins, a glowing endorsement.

"I dare to predict that John will outlast all the others," LaPaglia told ESPN.

"He's a big personality and Sydney's a big place, so you need a big personality to handle it.

"I really feel that John is the right match for the team and the players respect him."

LaPaglia, speaking at a charity match between his US-based team Hollywood United and David Beckham's LA Galaxy in aid of the recent California bushfires, also said he had no problem with Kosmina's fiery reputation.

"I didn't think twice (about his poor disciplinary record with the FFA), there's no such thing as bad press," LaPaglia said.

AAP