Longtime West Coast Eagles partner SGIO will conduct a rigorous review of its sponsorship of the club amid revelations star player Ben Cousins has been arrested over drugs.

Cousins' footballing future was in grave doubt today after he was charged following a traffic stop yesterday with possessing a prohibited drug - six months after leaving rehab.

The 29-year-old midfielder refused a blood test when pulled over in inner city Northbridge and was also charged with one count of failing to comply with a requirement to undergo a driver assessment.

Cousins has never tested positive for illicit drugs.

Earlier this year, the former Eagles skipper flew to California for expensive drug rehabilitation, returning to play for the club after apologising for his conduct.

His return to the football field was on condition he agree to a zero tolerance clause to testing positive to banned substances, stay away from underworld figures and not fall foul of the law.

West Coast was discussing Cousins' future today.

Major West Coast sponsors SGIO, a sponsor of the club since its inception 21 years ago, will also consider their future with the club in what the insurer describes as a standard review process.

"SGIO is mid-way through a three-year sponsorship of the West Coast Eagles and as with all sponsorships, we will be following our usual review process in the lead-up to the renewal," SGIO said in a statement.

"This review process will be thorough and rigorous and will be done with full support of the West Coast Eagles Club."

SGIO did not comment specifically on the Cousins affair in its brief statement.

But it said it trusted the club would deal appropriately with the matter.

"We trust the West Coast Eagles Club board and management will handle this serious matter in the most appropriate manner," the sponsors said.

Cousins will appear in the Perth Magistrate's Court tomorrow.

AAP