The Prime Minister has weighed in on Sonny Bill Williams' decision to cover up a bank sponsor's logo during a game, saying it's hard to understand why one player would act differently to the rest.

Williams put himself back in the news by taping over the BNZ logo on his Blues jersey in his Super Rugby comeback on Saturday night.

It's been seen as a religious stand by Williams, a devout Muslim, who was playing his first match in the 15-man game since the 2015 World Cup final after recovering from a ruptured Achilles tendon suffered at the Rio Olympics.

SBW with his altered jersey. Pic: Getty

Asked about it on Monday, Prime Minister Bill English reluctantly weighed in.

"It is hard to understand that one guy has to behave differently than the rest," he told Newshub.

"I don't understand all these professional contracts, but if you're in the team, you're in the team. You wear the team jersey ... But they'll sort it out."

RELATED STORY: SBW's religious reason for jersey alteration

While the NZR was unaware that Williams planned to plaster over the logo on his collar in Saturday's loss to the Highlanders, a spokesman told NZME wouldn't be a misconduct charge and it was an issue for the Blues to handle.

He said any player could lodge a conscientious objection to promoting finance, alcohol, tobacco, gambling companies and banks.

Blues assistant coach Steve Jackson said the matter would be addressed with Williams' management during the week.

A BNZ spokeswoman said the bank didn't have a problem with Williams' action.

"He's entitled to have religious beliefs and customs around that and it's really between him and the Blues as to how that manifests itself. So we have no issue with it," she told Fairfax Media.

NZ Newswire

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