Federal Opposition Leader Tony Abbott has sent an email encouraging people to donate money to the Liberal Party's campaign against the Government's proposed flood levy.

The Government plans to introduce the one-off levy for people earning more than $50,000 a year to help pay for the flood recovery. Flood victims and low-income earners will be exempt from the levy.

In the message to supporters, Mr Abbott outlines his opposition to the levy and says it defies credibility that the Government cannot find the money through budget cuts.

Mr Abbott's email against the levy provides a link to the Liberal Party's website where donations can be made.

A spokesman for Mr Abbott says the link was added by the Liberal Party headquarters.

In the email, Mr Abbott says the Government should not impose the levy to repay for infrastructure damaged by the floods.

"The Coalition is committed to doing everything necessary to get the infrastructure of Queensland, northern NSW and northern Victoria operational again. But we disagree with the Government on how to pay for it," the email said.

"We believe the costs for repairing and rebuilding infrastructure damaged and destroyed by the floods should come from budget savings, not from a new tax."

The email finishes with a line encouragaing donations: "PS Click to donate to help our campaign against Labor's flood tax".

The controversial legislation will be introduced when Parliament returns next week and the Government is facing an uphill battle selling the plan.

Crook's support

But Prime Minister Julia Gillard received a boost today with Western Australian Nationals MP Tony Crook announcing he would support the levy.

Under a deal struck with Ms Gillard, people in the flood-affected WA town of Carnarvon will not have to pay the levy.

Mr Crook has described the Government's proposed relief package as adequate and responsible.

He says it is important to support people in Queensland.

Ms Gillard has welcomed Mr Crook's support.

"I very much thank him for taking that approach in circumstances where the flood levy legislation is necessary to finance the rebuilding we will need to see in Queensland and in other parts of the nation."

Key independent MPs Rob Oakeshott and Tony Windsor have said they are not yet sold on the plan.