WELLINGTON, April 10 (Reuters) - Sonny Bill Williams's decision to cover up a sponsor's logo on his Auckland Blues shirt at the weekend was questioned by New Zealand Prime Minister Bill English on Monday.
The All Blacks centre put tape over the 'Bank of New Zealand' logos on the collar of his shirt when he made his return after seven months out injured in a Super Rugby match in Dunedin on Saturday.
The 31-year-old twice World Cup winner, who converted to Islam in 2008, said on Twitter that he would "clarify" his decision later this week.
"It is hard to understand that one guy has to behave differently than the rest," English told New Zealand radio's AM Show on Monday.
"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, you know, they'll sort it out."
New Zealand Rugby said Williams had a "conscientious objection" in his central contract that means he is not asked to do sponsorship work with banks as well as finance, alcohol, tobacco and gambling companies.
The "conscientious objection" is available to all players, an NZR spokesman said.
The Bank of New Zealand said it had "no issue" with the player's 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," said a spokeswoman.
The Blues said they were in the dark over the cover-up.
"The Blues did not know why the jersey was altered and is involved in discussions with Sonny, his agent and his employers, NZR, this week," said a spokesman.
Williams is one of his country's highest-profile athletes, having represented New Zealand at both rugby league and union as well as being the nation's former heavyweight boxing champion.
He ruptured his Achilles tendon while chasing Olympic gold with the New Zealand Sevens team at the Rio Games in August last year.
Williams came off the bench to make his Blues debut against the Otago Highlanders on Saturday, his first action in the 15-man game since the 2015 World Cup final, where he helped the All Blacks to victory over Australia. (Reporting by Nick Mulvenney, editing by Peter Rutherford)