Wellington Phoenix goalkeeper Mark Paston will undergo scans today on his injured knee.

Today marks the New Zealand international's 34th birthday but he will have no time to celebrate as he will be trying to learn the fate of what looks like a serious issue.

Paston, who missed the second part of last season with a knee problem, sustained the injury in Saturday night's 2-0 loss to Gold Coast United and is expected to be out for at least a number of weeks with the club remaining hopeful.

"Mark is an incredibly important asset to the club, so not having him available for any length of time is significant for us," said Phoenix chief executive Nathan Greenham. "It certainly appears Mark will be out of action for a matter of weeks but we'll be in a position to know more and to plan accordingly when the results of the scan are through."

Phoenix goalkeeping coach Jonathan Gould said it was another cruel blow for Paston but expects him to bounce back from whatever today's scans show.

"You could tell straight away he was in some amount of pain," the former Celtic goalkeeper said.

"Mark doesn't go down easily unless there's something wrong. Obviously he's not all right, but we'll just wait and see how the prognosis transpires over the next couple of days.

"Mark just seems to have quite a few cruel twists of fate.

"I know how hard he works on a daily basis. He's so dedicated to it and you feel really gutted for him."