The new schedule, which will begin in 2009, features fewer top-level events and a nine-week off-season - a fortnight longer than the current one.

Injury withdrawals from events by top 10 players more than doubled in 2006.

"Players deserve a longer off-season and healthier schedule so that they can avoid injury and fatigue," said WTA chief executive Larry Scott.

"In return fans deserve to see more players consistently performing at their best at our tournaments."

TOP-TIER EVENTS US: Charleston, Cincinnati, Indian Wells, Los Angeles, Miami, Montreal-Toronto, New Haven, Stanford. Europe: Berlin, Eastbourne, Madrid, Moscow, Paris, Rome, Stuttgart. Other: Beijing, Doha, Dubai, Sydney, Tokyo.

The number of Tier I and Tier II events will be cut to 20 from 26 with top players required to participate in 10 tournaments (in addition to the four Grand Slams), down from the current 14.

Four events will be mandatory - Key Biscayne, Indian Wells and new tournaments in Madrid and Beijing.

The women's season-ending Tour Championships will move to October from November to lengthen the off-season.

Top 10 players failing to play at tournaments as required will be subject to suspensions and larger fines than in the past.

The WTA Tour also announced that prize money will grow to an estimated $72 million (�54m) in 2009, 30% more than this year, and will be linked to commitments and revenue-sharing.

A new ranking system will be based upon 16 events and linked to the elite events with players missing a commitment taking a zero-point factoring into their ranking total.

The new nine-day tournament in Beijing is part of a major WTA push into China, where it will also open an Asian office.