The future of The Championships will be assured when legislation is passed to guarantee NSW has racing tax parity with Victoria.

Racing Minister and deputy premier Troy Grant will introduce the legislation in September after announcing in last month's budget the wagering tax would be decreased in increments over four years.

Racing NSW feared that unless it was put into law, the governing body would have to lobby at every phase.

The government gets $3.22 from every $100 wagered in NSW compared to Victoria where it is $1.28 - the figure NSW will be at by the end of the staggered tax decreases in 2020.

"This now provides certainty and means funding for The Championships," Racing NSW chief executive Peter V'landys said.

"It also means increases in country prize money.

"Now that it will be legislated, it means we don't have to reapply at every stage.

"The minister understood that without the legislation there was no certainty and he listened to what we had to say."

The tax cuts are expected to return $235 million to the industry over the next four years and up to $100 million per year once the lower tax is in place.

The Championships, run at Randwick over two Saturdays in April as part of the autumn carnival, offer $18 million prize money.

The Queen Elizabeth Stakes is now Sydney's richest race worth $4 million with the $2.5 million TJ Smith Australia's richest open sprint.

When it introduced The Championships two years ago, Racing NSW aimed to attract horses from overseas and so far horses from Japan, Ireland and England have made the trip.

Among this year's visitors was three-time Melbourne Cup runner-up Red Cadeaux who finished second to Criterion in the Queen Elizabeth Stakes.