The AFL has extended the sponsored countdown clock that appears on boundary advertising boards up until the final minute of the game for 2017.

Last season, a trial was conducted at games played at the MCG, in which the time remaining in the quarter would be shown once between the final 10 minutes and two minutes of the third and fourth quarters.

The final two minutes were kept secret to keep the tradition of fans not knowing how long is left, but it's been slightly tampered to now see just the final minute of the third and fourth quarters protected.

The countdown clock will still be shown once randomly throughout the quarter, and first utilised its extra minute in the game between Carlton and Essendon on Sunday.

The Blues led the Bombers by nine points with just 1:14 left on the clock, as fans and players inside the MCG knew exactly how long was left.