Each year backpackers and other visa holders descend upon the region's vineyards in the summer months to pick the grapes for wine production. But domestic and international border closures due to the coronavirus threaten to throw a spanner into that process this coming vintage.

Vineyard contracting business Prunerite employs up to 150 casuals for about 20 vineyards across the six week harvest, about 80 per cent of whom are backpackers.

Related: Picking time for the legendary Hunter Valley wine grape harvest

"Come harvest, there will be a massive shortage of labour," Prunerite co-owner Kyle Powell said. "I think we will be run off our feet this year with harvesting, because of the shortage of pickers.

"There's going to be a few disgruntled vineyard owners this year when they realise we can't provide staff for them come harvest."

Mr Powell said in coming weeks they planned to advertise to caravan groups and grey nomads to help fill the positions.

"We usually get a few of them after a bit of work," he said.

Hunter Valley Wine and Tourism Association manager Amy Cooper said while it was early in the season, the association was preparing for the borders remaining closed when harvest time hits.

"We're actively planning for it," she said. "We've been conducting surveys to capture what's needed.

"The NSW Government has also reached out wanting to know how we're tracking with the workforce."

Bruce Tyrrell of Tyrrell's Wines said he contracted about 70 to 80 grape pickers each harvest, who are predominantly backpackers and grey nomads.

"There's not going to be a lot of them around this year, but hopefully there will be some travelling within the state," he said.

He hoped local job seekers could help fill the gap, with the unemployment rate in the Hunter Valley sitting at 7.8 per cent in July.

"A lot of Australians are going to need a job, hopefully they can find work here."

The Federal Government's Joint Standing Committee on Migration is conducting an inquiry into the Working Holiday Maker Program.

The committee has made several recommendations to help fill regional and agricultural roles such as the government developing a 'Gap Year at Home Campaign' to attract young Australians to regional work, allowing workers to stay on JobSeeker while undertaking low paid agricultural and horticultural work, establishing a one-off payment to help with costs incurred working in regional areas and making amendments to visas for the next 12 months to make it easier for working holiday makers to take up regional work.