UPDATED 3.17PM There are calls to "match the money" at the star studded ASB tennis classic next month.

YWCA Auckland has launched a petition calling for prize money to be the same for both the men and women at next year's tournament.

The women's champion will get US$43,000 in prize money, while the men's winner will get almost double that.

LISTEN ABOVE: Nigel Yalden speaks to Tournament Director Karl Budge 

YWCA CEO Monica Briggs said the pay gap staggers belief.

"Of course this year with the Williams sisters coming over and their calibre of playing, it's really surprising that we still have a situation where men are paid virtually double," she said.

The overall prize pool for the women's tournament is US$250,000, while the men's pool is between US$460,000 and US$470,000.

Briggs said its time to match the money.

"We would love the money to get matched by progressive New Zealand businesses, [for them] to step forward and say 'this isn't right, we're gonna ensure that equality is seen to be done here',".

But organisers of the ASB tennis classic say those calling for pay equity for the tournaments are not comparing apples with apples.

Tournament director Karl Budge told Nigel Yalden the men's and women's tournaments are governed by different tours and have completely different business models.