Allaster said the Women's Tennis Association (WTA) had "zero tolerance" to abuse. But she added that tennis had many positive examples of parents who coach, and said it would make no sense to limit family involvement.

"I think we've got great examples of fantastic parents who have been coaches. So we shouldn't cast anything on one parent going off the wall on all parents involved in tennis," the WTA chairman and CEO told AFP.

"What is critically important is that we have zero tolerance for behaviour that is abusive, and educating our athletes and having the professional code in place and if required, we execute."

Allaster was speaking at Wednesday's announcement of Singapore as host of the season-ending WTA Championships from 2014-2018, a coup for the city-state and for tennis as it seeks to expand its popularity in Asia.

Two days earlier in Madrid, John Tomic was charged with assault for headbutting his son's training partner Thomas Drouet and breaking his nose. He denies the charge, and says he was acting in self-defence.

Australian media and former players have urged 20-year-old Tomic, the country's number one, to dump his father as coach after the incident, which revived memories of previous episodes involving tennis parents.

In 2009, after several flare-ups on tour, Jelena Dokic's father Damir was jailed in Belgrade for threatening to attack the Australian ambassador with a hand grenade.

France's Mary Pierce eventually took out a restraining order against her father amid allegations of assault. Jennifer Capriati and Steffi Graf are two other stars who had difficult times with their fathers.

And in 2011, French player Aravane Rezai asked the WTA to bar her father, Arsalan, from tournaments after a confrontation at the Australian Open.

Allaster said the WTA, mindful of the dangers, had a "rookie" system in place to educate youngsters about possible abuse, and also a director of athlete assistance to look out for players on tour.

And she cited Richard Williams and Oracene Price, the parents of Venus and Serena Williams, Piotr Wozniacki and Martina Hingis's mother as examples of "great tennis parents" who have moulded and benefited their children's careers.

"The WTA has zero tolerance for any kind of behaviour, whether it be a parent, a coach, a fellow player, for any sort of abuse," she said.

"We have a strict professional conduct and if required we have no problem banning support team members from our environment. We have done that in the past and we'll continue to do it in the future."