There is growing unease on the Coalition backbench at the possibility the Turnbull Government will take a Goods and Services Tax (GST) hike to an election.

The ABC has been told that as many as 20 MPs are organising against the move.

Key points: About 20 backbenchers are worried about the impact a GST rise will have at the polls

About 20 backbenchers are worried about the impact a GST rise will have at the polls Increasing the tax from to 15 per cent could raise $46 billion annually

Increasing the tax from to 15 per cent could raise $46 billion annually Nationals MP says government needs to properly inform public of benefits

The key concern is that the Government is moving towards an increase in the GST from 10 to 15 per cent without adequately considering other measures, such as changes to superannuation and negative gearing.

Federal Liberal director Tony Nutt is believed to be holding briefings for MPs in marginal seats on a range of issues that will arise during the election campaign, including the GST.

One MP has told the ABC there is a feeling that while Prime Minister Malcolm Turnbull is happy to discuss broad changes to the taxation system, his Treasurer Scott Morrison's focus remains on the GST.

Treasury has modelled the impact of increasing the GST to 15 per cent, expanded to include food and non-alcoholic drinks, as well as water and sewerage charges, raising as much as $46 billion annually.

Mr Morrison continues to argue the Government is having a wide-ranging debate on taxation, and would never play into Labor's game of ruling things in or out.

Victorian Nationals MP Andrew Broad told ABC Radio National there were some rumblings among his colleagues.

"If any conversation becomes too one-dimensional, it of course scares people, and I guess there's some nervousness and some discussion there," Mr Broad said.

Mr Broad said the Government needed to sell the potential GST increase by showing it would boost job numbers and reduce property stamp duty.

"But if we're going to the Australian people saying 'well we're just going to take an extra 5 per cent, and trust us we can spend your money better than you can spend it,' well I wouldn't support that and I don't think the electorate would buy it," he said.

The Government has promised its tax plan would be released before the election later this year.