The NBA Board of Governors unanimously approved two big changes that will affect the upcoming season.

The league will now allow a coach's challenge and give replay centers the ability to prompt instant replay.

Coaches will now be able to challenge personal fouls charged to their respective team, a called out-of-bounds violation as well as goaltending and basket-interference violations, the NBA announced on Tuesday.

The replay center, along with the refs calling the game, can ask for instant replays involving whether a shot is a two- or three-point field goal, and if it was made before or after the shot clock expired.

"These initiatives further strengthen our officiating program and help referees make the right call," NBA president, league operations Byron Spruell said in a statement.

"Giving head coaches a voice will enhance the confidence in our replay process among teams and fans and add a new, exciting strategic element to our game.

"Enabling the NBA Replay Center to trigger instant replay will improve game flow and provide real-time awareness of any adjustments to the score."

A version of the coach's challenge has been in effect in the G League for the past two seasons and is being used at this year's Summer League. It will be adopted in the NBA on a one-year trial basis during the 2019-20 season.

Some key points to the coach's challenge, outlined by the league, include:

- To initiate a challenge, a team must immediately call a legal timeout and the head coach must immediately signal for a challenge by twirling his/her finger toward the referees.
- If a team attempt to challenge an event with no remaining timeouts, the team are charged an excessive timeout, for which the penalty is a technical foul, and no challenge will take place.
- If a team call a timeout to challenge an event that may not be reviewed, the team will be charged a timeout but retain their challenge.
- As with other replay reviews, in order to overturn the event as called on the floor, there must be clear and conclusive visual evidence that the call was incorrect.

The NBA had already taken steps to be more transparent in the officiating process last season by having centralised replay center make the "last two minute" reports on officials public.