A Senate Economics Committee report on the backpacker tax has been delayed until Wednesday, the ABC understands.

The committee was due to return its verdict on Monday, following a snap inquiry into a range of new measures including a 19 per cent income tax rate for working holiday makers.

Labor pushed for hearings after the Coalition backflipped on its original plan to enforce a 32.5 per cent tax on all backpackers' earnings, from the first dollar.

During public hearings, Treasury officials told the committee the government never modelled the impact of higher backpacker taxes on the agriculture sector or the economy.

The Opposition said it would declare a position on the proposal - a 19 per cent tax rate for backpackers, who will also lose 95 per cent of their superannuation in tax when they leave the country - after the inquiry reports back.

On Sunday, Labor leader Bill Shorten told the ABC Insiders program that the Opposition was "open to" a 10.5 per cent tax rate.

Queensland growers see drop in enquiries

In the Queensland food bowl of Bundaberg, issues about backpacker pay and conditions have long been an issue.

Allan Mahoney manages a farm for Perfection Fresh, a family-owned company that grows and markets fresh fruit and vegetables all over the country.

He said the need for labour, particularly in the blueberry lines, could skyrocket from 12 to 200 almost overnight.

"When we are in full swing and picking, we will raise up to 130 to 140 a day in the field and 60 in the shed ... so we are over 200 a day," he said.

"It is a pretty unique situation with the berry crop [but] it's not a unique situation in this area though, within the region you always have crops coming in to play where you need to raise your amount of workforce hugely overnight.

"It takes a lot of planning and we need that backpacker trade."

He said the ongoing discussion about the tax had already had a significant impact on the $2.5 million turn over business.

"It's a massive issue that has come to play and we just really want it over with so we can start planning ahead.

"International travel has dropped between 7 and 14 per cent already, we've seen the numbers.

"Enquiries for next season, we've had people that usually book in for each season to come on farm, they don't know, they're not quite sure [about coming back], they want to see what happens."

Mr Mahoney, the chairman of the local fruit and vegetable growers group, said the industry could live with the 19 per cent compromise.

Tasmanian apple grower Howard Hansen, the first Australian apple grower to send apples direct to China. ( Supplied )

Tasmanian orchardist refutes claims backpackers don't pay tax

Southern Tasmanian fruit grower Howard Hansen is a leading grower and exporter of apples and cherries and one of the first to export to China.

He said his business expanded when harvest labour was guaranteed, after the Australian Government extended working holiday visas for people who completed 88 days' work in a regional area.

"That single decision fixed the labour supply problem," Mr Hansen said.

"Prior to that, not so much in Tasmania, but certainly in mainland Australia with citrus and grapes and a range of products, the crops were falling on the ground.

"That is the risk."

In a submission to the Senate Review into Working Holiday Visas, Mr Hansen argued a 19 per cent tax on backpackers risked his entire industry, including the jobs of his Australian employees, who comprised two thirds of his payroll.

He said a 19 per cent backpacker tax, plus 8.78 per cent superannuation (27.78 per cent in total) would make his industry uncompetitive with New Zealand and Canada.

Mr Hansen said it was a myth that backpackers working in Australian orchards were not paying tax.

"We estimate that of the $6.5 to $7 million payroll that we payed last year over 35 per cent of that is going to people on a working holiday visa.

"We are using the tax table for the horticultural industry and the shearing industry, so every single one of them we're taxing them at 13 per cent.

"There's been a misconception across this whole debate, everyone was of the opinion that these people are not paying tax.

"Well I can confirm in our business every single one of them is paying 13 per cent."

That tax can be refunded to backpackers that earn less than the tax-free threshold through a tax return.