Former Australian Test captain Steve Waugh has warned that Ricky Ponting cannot go on forever despite his stellar form and selectors must start planning for his eventual departure.

Ponting, 37, was in sparkling form in the recent Test series against India, shrugging off speculation about his future by becoming only the third batsman in history to pass 13,000 Test runs, scoring 544 runs at an average of 108.8.

But Waugh, who played until he was 38, said some hard decisions needed to be made before next year's Ashes series against England.