The Premier Lara Giddings today called on the Liberals Party to stop misleading Tasmanians and being apologists for Tony Abbott's push to slash GST revenue to the State following damning evidence a Coalition government would change the funding formula.

Ms Giddings said Shadow Assistant Treasurer Senator Matthias Cormann's admission at the weekend that the Coalition would move to change the distribution of GST to the States was undeniable proof of their plans.

"I welcome Will Hodgman belatedly getting behind the Government but he must now convince the likes of Eric Abetz and David Bushby to stop making excuses and trying to mislead Tasmanians over Tony Abbott's plan," Ms Giddings said.

"We now have Tony Abbott who wants to the prime minister, his deputy Julie Bishop, would-be treasurer Joe Hockey and now his assistant Senator Cormann all saying they want to change the current arrangements.

Ms Giddings said claims by Senator Bushby that the States could veto the Coalition's GST plan were misleading.

"Under the current Intergovernmental Agreement on GST, the Federal Treasurer determines the sharing arrangements and can decide the extent to which they are prepared to accept Commonwealth Grants Commission's advice.

"The Federal Treasurer also issues Terms of Reference to the Commission and this can have a significant impact on how the CGC prepares its advice to the Treasurer.

"Regardless of this, if the States have veto over changing the distribution of GST why is Tony Abbott and his prospective leadership team making promises that they can't fulfil?

"If we have a Federal Government that believes the GST should be determined "closer to a per capita arrangement" (Tony Abbott, The Australian, 1 May 2012)then the consequences for Tasmania will be disastrous.

"The Liberals will only commit to saying Tasmania should not be worse off but no one knows what that means.