AN LED countdown clock can now appear at the MCG up until the final minute of games.

In a trial launched last season, the AFL allowed the MCG's boundary advertising boards to be transformed into a countdown clock for 40 seconds in each of the third and fourth quarters.

To preserve the tradition of players and fans at the ground being unaware of how much time was left before the siren, the countdown clock was used between 10 minutes and two minutes to go in both quarters.

However, the countdown clock appeared less than two minutes before the final siren in Carlton's win over Essendon on Sunday.

An AFL spokesperson confirmed on Monday the countdown clock would now be permitted to run up until the final minute of third and fourth quarters.