New Zealand midfielder Tim Brown will undergo surgery on the shoulder he injured against the Socceroos in a bid to keep his World Cup dream alive.

The All Whites vice-captain fractured his humerus in a challenge with Australian midfielder Vince Grella in his team's 2-1 defeat at the MCG on Monday night.

New Zealand Football said in a statement on Wednesday that Brown would undergo surgery on Thursday and would need a few days after to recover before being reassessed.

Brown had said on his return to Auckland before heading for his medical assessment that his presence at the World Cup in South Africa starting on June 12 had been rated at "50-50".

"I'm trying to be real positive about that at the moment," he said.

"But there's also the chance I won't be able to go. If that's the case, I'll put my hand up straight away and someone else can take my place. I'm not going to muck anyone around."

Brown, 29, who has been capped 25 times, said he was taken aback by the "amazing" support he had received from his team-mates, with plenty of texts and other messages constantly arriving.

The All Whites have headed to Europe for two further friendly matches.

If Brown does not make the World Cup, he will be a significant loss for coach Ricki Herbert as the All Whites prepare for their opener against Slovakia on June 15.

Herbert said Brown would be given every opportunity to rejoin the squad, but the time needed for rehabilitation could rule that out.

Wellington midfielder Cole Peverley, one of seven players on stand-by to cover injuries to the 23-man squad, is the likely replacement should Brown be ruled out.

Brought to you by AAP © 2024 AAP