YORKSHIRE'S overseas player Kane Williamson has been banned from bowling in all cricket due to an illegal action.

The New Zealander, primarily a batsman, bowls useful part-time off-spinners, which have brought him eight wickets in County Championship and Twenty20 cricket combined this summer.

Williamson was reported for a suspect action during a recent Test series in the West Indies, and he had his action tested at Cardiff University on July 9.

The results were published today, with the ICC saying "most of his deliveries exceeded the 15 degrees level of tolerance (relating to the extension of his right elbow) permitted under the regulations".

Williamson will only be allowed to recommence bowling duties once he has had his action legalised, which could happen before the end of the season.

However, there is the distinct possibility that Williamson could miss the last two Championship matches of the campaign anyway due to commitments with the Northern Knights at the Champions League T20 through mid to late September.

"I note the findings of Dr Craig Ranson and his team at Cardiff Met and will concentrate on changing whatever's necessary to return to the bowling crease," said Williamson.

"The onus is on me to satisfy assessors as to the legality of my action and I'm aware I have some hard work in front of me."

Yorkshire coach Jason Gillespie has backed his player to overcome the setback: "We're obviously disappointed for the individual, but rules are rules.

"We know Kane works incredibly hard on all facets of his game and there's no doubt he'll be working hard to be back bowling sooner rather than later.

"Already, up at Scarborough in preparation for each day's play of our game against Middlesex, he was working on his bowling and trying to change his action to fit within the laws of the game.

"It's not ideal (for us) because Andrew Gale has been able to rely on Kane for a few overs here and there.

"We have to work with him and help him as much as we can whilst he's with us at Yorkshire."