A former Aboriginal police liaison officer has been found guilty by a District Court jury in Carnarvon in Western Australia over his part in a drug deal.

Revel Roland Oakley, 51, and three of his relatives were charged after an undercover operation in March last year.

It was the prosecution case that the group planned to buy almost four kilograms of cannabis from a supplier.

Oakley has been remanded in custody to be sentenced next month.

His wife received a 12-month suspended sentence after pleading guilty to a charge of conspiring to possess cannabis with intent to sell or supply.

Two other relatives pleaded guilty earlier this year and also received suspended jail sentences.