Tournament direct Craig Tiley said the decision on implementing the policy will take into account the weather forecast once the temperature exceeds 40 degrees Celsius (104 degrees Fahrenheit) and the Wet Bulb Global Temperature - a measurement that accounts for humidity, wind direction and the temperature - exceeds a reading of 32.5.

"We believe this update will clarify and streamline the communications process for both players and support staff," Tiley said. "We've consulted the playing group and this is seen as the fairest way to implement the policy by many of the top players."

The tournament referee still has the absolute discretion on whether or not to apply the extreme heat policy, organizers said, although setting the parameters will help players and coaches preparing for matches.

In the other change, matches in progress when the extreme heat policy is invoked will be suspended at the end of an even number of games in that set or at the completion of a tiebreaker.

With the recent opening of the remodeled Margaret Court Arena, the Australian Open has three courts with retractable roofs for 2015. Organizers said that will help weatherproof the tournament.

The temperature topped 40 degrees C (104 degrees F) for four consecutive days during the tournament in January, the longest heat wave in the city in a century, but the extreme heat policy was rarely implemented.