NBC Sports is also reporting the deal has been secured.
Adams, 23, has made a bright start to his fourth term on a rookie salary, helping the Oklahoma City win their first three games.
His growing influence last season helped steer them to the Western Conference final, raising his stocks considerably to be rated among the best centres in the league.
With key scorer Kevin Durant and tough forward Serge Ibaka departing in the off- season, prolific guard Russell Westbrook and Adams are regarded by pundits as central figures at the Thunder over coming seasons. Westbrook re-signed on an undisclosed deal in August.
If Adams earns $35m per year, he will comfortably eclipse New Zealand's other big earners.
US-based America's Cup sailor-turned-official Russell Coutts is widely thought to be the best renumerated at about $13m annually, narrowly ahead of West Ham defender Winston Reid and IndyCar driver Scott Dixon.
-AAP