Federer and Nadal will both be absent from Paris

De Villiers said he was "disappointed and concerned" after Roger Federer pulled out, meaning five of the world's top six will miss this week's event.

"This reinforces my determination to introduce meaningful change to the calendar," said De Villiers.

Tournament director Cedric Pioline wants bans for serial absentees.

This is the third year that withdrawals and injuries have hurt Paris and the fans' opportunity to see all their tennis idols Etienne De Villiers, ATP chairman

"The tournament organisers seem to have more obligations than the players," said Pioline, a former top-10 player.

"We need a system with sanctions and, having been a player, I can tell you that fines don't work. We need bans."

Federer withdrew on Monday citing tiredness, while Rafael Nadal is injured and David Nalbandian has a stomach problem.

World number four Ivan Ljubicic and number six Andy Roddick pulled out earlier, having already qualified for the season-ending Masters Cup which begins in Shanghai on 12 November.

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Sandwiched between the Madrid Masters and the Masters Cup, Paris has been hit hard by withdrawals in recent years.

"Unfortunately this is the third year that withdrawals and injuries have hurt the event and the fans' opportunity to see all their tennis idols," said ATP chairman De Villiers.