Kim Clijsters' 2006 was blighted by injury - she plans to retire next year

Late withdrawal fines will be doubled to a maximum of $40,000 (�21,000) for third and subsequent late withdrawals.

The WTA also plans to reduce the minimum tournament requirement from 13 to 12 events, including two chosen by the Tour for each player.

The WTA Tour has been blighted by an increasing number of late withdrawals by top players in recent years.

"Today's package of reforms is an important step forward to ensure we are able to deliver to fans and tournaments the players that they want and deserve to see on the court, and to protect the health of our players," said WTA Tour chief Larry Scott.

I am very excited that 2007 will bring our fans more excitement and accessibility than ever before WTA Tour chief Larry Scott

"The data on player withdrawals caused by injury and fatigue is undeniable, and the solutions are equally clear to our players, tournaments and partners - a shorter season, more breaks for players and reduced requirements on top players."

The commitment requirement for players on the Tour for 12 events or more is also being reduced by one tournament.

And there will be an option for players aged 30 or older to have their minimum commitment consist of only four Tier One events.

The testing of on-court coaching will continue at all top level Tour events following the Australian Open up until the French Open at Roland Garros in 2007.

The Tour plans to propose legalising coaching from the stands. Citing difficulty in policing coaching, it will set parameters to ensure no disruption or interference with play.

"Sport lives or dies by the fan experience, and I am very excited that 2007 will bring our fans more excitement and accessibility than ever before," Scott said.

"Our on-court coaching test this past autumn showed us that fans and broadcasters like the added drama that live coaching brings to the game."