Players at next year's Australian Open are guaranteed harder tennis balls and guaranteed shelter from the scorching heat, the tournament's organisers said yesterday. The first grand slam event of the season was hit this year by a heatwave which led the organisers to shut the roof on the centre court when temperatures soared above 35 degrees Celsius.

"This year, we basically just had a roof policy," said tournament director Paul McNamee. "But next year, we will have an overall heat policy which will include when to shut the roof."

He said the new policy would include when to suspend play on outside courts.

The roof policy sparked controversy this year, with some players who had prepared themselves to play in the Melbourne heat furious about playing in air-conditioned comfort.

But others wanted matches rescheduled when court-side temperatures reached as much as 50 degrees.

Big serve-and-volley players also complained last year that the balls used in the Australian Open were too soft and slow and were causing wrist and elbow injuries.

McNamee, who this year defended the balls, said that next year's tournament would have new, less fluffy balls.

"There was too high a percentage of balls that were rejected last year and we would not be happy if that situation occurred again this year," he told a news conference to launch the 1998 Open yesterday.

"Slazenger, however, have continued to look at evolving their balls and the end result of that will mean there will be less fluffing of the balls and as the game proceeds, instead of the ball getting slower, it will get faster."

Prize money next year will be lifted by five per cent to £7.2 million, organisers said.

Former women's number one Steffi Graf is expected to make her return from injury and current singles champions Pete Sampras and Martina Hingis have both confirmed they will defend their titles.