The standard of refereeing in the NRL has come under fire again with coaches from both the Warriors and North Queensland claiming officialdom wasn't up to scratch in their clash in Auckland.

Cowboys coach Neil Henry questioned whether referee Ashley Klein was up to NRL standard after his side's 24-12 loss on Saturday night but Warriors coach Ivan Cleary was equally critical.

Cleary claimed the referee failed to award several clear-cut penalties and questioned the point of sending Cowboys centre Willie Tonga to the sin bin after a scuffle on the fulltime siren.

"The end of the game I thought was a farce," Cleary said.

"That just should have been like the game was over, there was a bit of a scuffle, there was nothing much, it certainly wasn't a penalty.

"Willie Tonga was having ten minutes and the game was over.

"Just call it off and go home.

"It's ridiculous."

Henry said Klein made errors against both sides.

"If Ashley Klein is up to standard - I don't know," he said.

"I don't know where his head was at.

"To be fair too, I think the Warriors probably got a couple of call too.

"I think it was one of those games."

Cleary said he saw "half a dozen" penalties that should have been awarded under the referees' key indicators.

Henry and Cleary weren't alone in their criticism of referees over the weekend with Sydney Roosters coach Brian Smith and Canberra's David Furner among others voicing their frustration at officials.

The comments come on the back of calls last month for NRL referees boss Robert Finch to scrap the dual referee system following a controversial match between Parramatta and South Sydney in which both officials were accused of losing control.

Meanwhile, hulking Warriors winger Manu Vatuvei will have further scans this week to determine the nature and seriousness of the injury that forced him off against the Cowboys.

Returning from a month out with a hamstring problem, Vatuvei lasted only four minutes into the second half after he was hurt in a 13th minute tackle.

The club said on Sunday x-rays on Vatuvei's lower left leg had shown no break but he would undergo further checks.

Cleary insisted it was not a recurrence of his hamstring strain.

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