Melbourne star Billy Slater will be out of action for a month in the NRL with a shoulder injury.

Slater aggravated an old injury in his left shoulder in the first half of the Storm’s Easter Monday win over the Warriors.

Scans on Wednesday afternoon confirmed the damage, with the Storm announcing Slater would have four weeks off.

“After consultation with the club’s medical staff, it was determined this was the best course of action to allow the joint to settle down and strengthen,” Melbourne said in a statement.

Slater had surgery on his right shoulder at the end of last season.