The price of fruit and vegetables — especially the summer mango — for Australian consumers is likely to increase if the backpacker tax is not axed, the peak Northern Territory farming lobby group has warned.

Key points: Survey shows commercial NT growers almost exclusively rely on backpackers to get product to market

Farmers expect backpacker employment to decrease up to 80 per cent if tax is introduced

NT Farmers Association warns effects of tax would be felt by all NT businesses

NT Farmers Association chief executive Shenal Basnayake said half of Australia's mangoes came from Territory farms.

He said a new survey showed commercial NT growers — who often need a big workforce for only short periods during yearly harvest — almost exclusively relied on backpackers to get their product to market.

"If you see not enough backpackers taking fruit off the tree … the end result will be an increase in price, I would say," Mr Basnayake said.

"You'd have less fruit on the market, and obviously that becomes more valuable, and then the cost will be borne by the end consumer."

The NT Government-run survey polled almost 200 farmers about the tax, which would see overseas workers taxed at 32.5 per cent.

Nearly half of respondents expected the number of backpackers they employed would decrease between 20 per cent and 80 per cent.

Backpackers make up 25 per cent of Australia's farm workforce, according to statistics from the National Farmers' Federation.

But the NT Farmers Association has calculated backpackers represent 85 per cent of the Territory's farm workforce, based on the survey results.

Ross Maxwell, manager of Jabiru Tropical Orchards, runs a mango farm just outside Darwin.

He said he had about five or six permanent staff, but during the four to eight-week harvest period, which starts about October, he would need another 120 people to pack at least 180,000 trays of mangoes.

"Without them [backpackers] we wouldn't have a mango harvest. It's as simple as that," Mr Maxwell said.

He said they sourced as many locals as they could, and also used a Facebook page to keep anyone interested up to date with harvest timetables and work opportunities.

But he said in reality the vast majority of the harvest staff were backpackers.

Flow-on effects would be felt across NT

NT Primary Industry Minister Gary Higgins said farms in other states might be able to source more locals but there was little incentive for Australian workers to come up to the Territory.

"If you're just driving yourself, you're looking at about $1,000 in fuel," Mr Higgins said.

Primary Industry Minister Gary Higgins says there is little incentive for migratory workers to come to the Territory. ( ABC News: Frank Gosper )

Mr Higgins said it was time for the Federal Government to make a decision on the tax, even though it had previously said it would make a decision on the looming tax by January.

He said backpackers were already starting to plan their holidays for next year.

Mr Basnayake said the flow-on effect would be felt across the horticultural centres in the NT, particularly the smaller townships, which benefit from backpackers staying and spending their earnings.

"Definitely the tourism sector … the retail sector, the restaurants and just the general community — the fuel stations and the newspaper joints — every business has an impact."