Waratahs superstar ruled out for up to a month

The Waratahs have suffered a crucial injury to Wallabies superstar Israel Folau that will sideline him for up to four weeks after he limped off early with a hamstring injury against the Brumbies.

"They've had a scan. I believe it's more muscular than tendon-based and it's going to be four weeks at this stage," Waratahs attack coach Chris Malone said.

The team is confident they have the personnel to keep their season rolling, with replacement Alex Newsome playing well in Folau's place on Saturday.

"Alex Newsome came on and played for most of that game and played really well so he's a genuine option.

'You've got Cam Clark coming back from injury.

"Obviously Bryce Hegarty (is) playing 15 and going well so there's a few options for us in those wide channels."

The Waratahs will be hoping that Folau will be able to return before a daunting stretch during May that sees the Sydneysiders face four New Zealand teams in a row.

The team travels to Japan to play the Sunwolves in Tokyo before returning home to play the Reds and Lions. They will also be without current Wallaby halfback Nick Phipps who is still recovering from a calf injury.

"It's pretty frustrating for him. Phippsy (looking at) his face, he's not a happy man, but unfortunately that's just what we've got to do to make sure that he lasts the whole season."

The Waratahs will look to rely on other players in attack, such as Fijian winger Taqele Naiyaravoro who has hit a purple patch in form, scoring a double in his last two games.

Malone heaped praise on what the big man brings to the Tahs.

"He gives us line bend. He gets to the gain line quite well off set-piece," he said.

"He's a big bit of meat but when he gets his timing right he's hard in motion to stop.

"He knows there's areas to work on but he's a weapon. He does some damage."