New Labor leader Michael Daley last month warned the SCG Trust and NSW Government not to begin work on demolishing the stadium because a future Labor government would withdraw all state funding.

Today though NSW Liberals pledged to push on with the demolition and construction of a new 45,000-seater, $750m stadium over the next three years.

The development has already seen Sydney FC leave the stadium to play this season's games at the SCG, Jubilee Stadium and Leichhardt Oval until construction work is complete.

The NRL has pledged to play all grand finals at the new stadium for the next 25 years - but threatened to take them interstate if the work did not go ahead.

Today both hailed the decision to push on with the redevelopment.

“We are extremely pleased with the speed at which the government is executing on its plans for the new state of the art stadium in Moore Park,” said Sydney chairman Scott Barlow.

“Today’s signing is a huge step forward in ensuring our club won’t be displaced for any longer than necessary.

“It gives us confidence that the project will be completed in the original time frame and our many thousands of fans will be entering a new world class facility sooner rather than later.”

And NRL chief executive Todd Greenberg added: “Today is another crucial step in delivering that agreement.

“Our fans deserve the very best facilities to enjoy rugby league live and the Sydney stadia rebuilds will deliver this.

“I look forward to following progress and like thousands of our fans, I look forward to sitting in the crowd at a brand new Sydney Football Stadium.”

Rugby Australia also welcomed the decision.

“Rugby Australia has in place significant content deals with the NSW Government which are predicated on its stadiums plan being delivered," said chief executive Raelene Castle.

“We have continuously stressed the need for world-class stadiums in Sydney to attract the biggest events, such as the Rugby World Cup. These events not only position Sydney as a truly global city but deliver significant economic impact to the State.

“In order to attract fans to our games, new and old, we need our stadiums to match their expectations in terms of accessibility, amenity, technology, comfort and overall experience.

“We look forward to working with the successful contractor to ensure that the new Allianz Stadium delivers on this and provides a safe and enjoyable experience for all.

“The NSW Government under Premier Gladys Berejiklian have shown strong vision and leadership in forging ahead with plans to deliver world-class stadiums for New South Wales.”