Internal government anger over the backpacker tax is continuing to grow, with a first-term Tasmanian Liberal senator calling on the Prime Minister to intervene.

The Federal Government has delayed the 32.5 per cent tax for six months after a backlash from the agricultural sector.

It had planned to remove the $18,200 tax-free threshold for overseas workers, making them pay tax from the first dollar earned.

The ABC has been told a 19 per cent compromise is more likely, but no final decision has been made and the changes are being reviewed.

Tasmanian senator Jonathon Duniam has been lobbying against the tax, and now wants Prime Minister Malcolm Turnbull to personally intervene and make a final decision.

"What I am doing is appealing to the Prime Minister to provide that certainty to give our economy the certainty needed going into this harvest season," he said.

"Certainty for me is a final decision so that people know what we are going to be playing with moving forward."

The agricultural industry has been lobbying hard against the tax, as have backbenchers from across the country.

Senator Duniam said it was time the concerns were listened to.

"Canberra needs to get out and hear what the real world and the rest of the country is thinking and feeling about certain issues and that's why I am being so vocal about this issue."

Not too late for coming season: farmers

It is estimated enquiries for seasonal work are down in Tasmania by as much as 40 per cent.

Tasmanian Farmers and Graziers Association believes people were being deterred from coming by the lack of assurance about a final figure.

"The rumours that are out there that we are going to put this tax on is certainly already driving some away," president Wayne Johnston said.

He believes it not too late to secure workers for the coming season, but informing backpackers when a decision is made is crucial.

"I think social media will need to be used to let people know that we are ready to take them on," he said.

Any changes to tax rates for working holidaymakers are due to start from January 1.

National Party MP Luke Hartsuyker, who is in charge of the Government's review, has been contacted for comment.