Labor needs to come clean over its continuing power hoax and immediately submit its latest promise to be costed by Treasury under the Charter of Budget Honesty.

Two announcements in two days have chronically underestimated the cost to Tasmanian taxpayer.

Labor has:

⦁ costed its household rebate and price cap at $50m when the real cost is likely to be at least $276 million; and

⦁ costed their proposal to reimburse businesses for power used over 100MWh at $20milion while admitting they have no idea of the real cost.

Labor's hapless energy spokesman has today told the Mercury:

"The cost of the policy is a function of the difference between wholesale prices and the cap. However, Tasmania's ownership of Hydro Tasmania means that those high wholesale prices lead to higher profits to Hydro Tasmania - which we will use to recover the cost of the program."

Treasurer, Michael Ferguson, said Labor is again relying on its magic money tree.

"Their reckless policy will cost far more than Hydro's dividend and a recipe for more Labor budget cuts: its time Labor revealed their secret plan for new taxes and cuts that would pay for it," Mr Ferguson said.

"The last time Labor was in government they promised a price cap before the election, only to back down after revealing the true cost and admitting the plan was a 'cruel hoax'.

"Labor has not learnt their lesson but want to continue to trick Tasmanians.

"Tasmanians deserve better.

"Only a Rockliff Liberal Government will continue to deliver the nation's lowest power prices and targeted affordable power bill relief."