That's the warning from the vegetable industry's peak advocacy body, who say some growers may be forced to leave unpicked produce to rot.

AusVeg public affairs manager Tyson Cattle said farmers were struggling with a shortfall of more than 20,000 workers blocked from entering the country by COVID-19 travel restrictions.

"It's hard to gauge, but certainly we'd expect to see natural supply and demand affect prices because the productivity is down," he said.

"I think at the end of the day it's going to vary from location to location. So if you're talking to a smaller grocer who's got their own supply contracts with a local grower it's going to be different depending on where you are in Australia."

NSW Riverina-based Wagga Fruit Supply grocer Steve Papasidero said prices would increase if farmers are unable to find workers.

"If there is a labour shortage, then definitely. But there are people looking for work everywhere, hopefully they can find their way to pick some fruit for us," he said.

The Australian Bureau of Agricultural and Resource Economics and Sciences predicts the price of summer vegetables, stone fruit, table grapes, pears and apples will rise by 15 to 25 per cent this year.

However, Mr Papasidero said prices were still "looking good" despite looming workforce issues because farmers were enjoying a booming harvest.

"We haven't really seen that much yet. It depends on the type of fruit and vegetables because they're all picked at different times," he said.

"It's been a good Christmas ... compared to this time last year, things have been better price-wise."

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Spokespeople for Coles and Woolworths said popular summer fruits were currently "in good supply" at the supermarket giants.

A Coles spokesperson acknowledged some growers were experiencing difficulty in securing seasonal workers to harvest or pack their crops.

"It is difficult to quantify the potential impact of labour shortages in the horticultural sector, but we're hoping it can be minimised both for farmers and customers," the spokesperson said.

"Where necessary, Coles has worked with suppliers to adjust sourcing arrangements, such as delivery schedules, to provide flexibility for farmers and maintain supply for our customers."

"We also continue to liaise with State and Federal governments regarding their proposed initiatives to address the issue of labour shortages in the horticultural sector," they said.

A Woolworths spokesperson said fresh fruit and vegetable prices had remained fairly stable in line with usual seasonal variations.

"We're closely monitoring the impact of labour shortages with our growers and supporting them through these challenges as best we can," they said.