Industrial action at four giant warehouses in Victoria and NSW would likely cause serious problems for Woolworths in supplying its supermarkets and liquor stores.

The workers are pushing for much improved job security, more full-time work, greater redundancy pay-outs and wage increases of $2 an hour, per year. Depending on their wage and experience that could equate to well in excess of 6 per cent a year.

The National Union of Workers last week applied to the Fair Work Commission for the right to take industrial action at three distribution centres in Victoria and another in NSW.

The strikes would cause most disruption in Victoria with the warehouses at Broadmeadows, Laverton and Wodonga key to its local supply chain. Woolworths fought the application and a decision has yet to be made on it by the workplace tribunal.

The union's industrial officer Dario Mujkic??? said talks over new workplace agreements had stalled.

"Primarily, our members want a fair share of their employer's profits, and job security now and into the future," he said. "This isn't unusual, these are two of the most important issues for NUW members across the country."

A Woolworths spokesman did not comment directly on the union claims or the possible effect on its supermarkets. "We will continue to work with our team members and their chosen representatives to get the right outcome at each of our sites," the spokesman said.

"Our number one priority will remain our team members and the service to our customers."

Dozens of union delegates from Woolworths met last week. Julie Kamber???, a delegate from the Hume distribution centre in Broadmeadows, said her site, which employs about 700 workers, faced added uncertainty as it will close.

Hume will be replaced by a site in Melbourne's east that will employ far fewer workers due to the much greater use of automation.

"There's still no date of closure, it leaves a person in limbo," she said.

Ms Kamber has spent 13 years at Woolworths, doing picking and packing of goods. Workers at Hume want retraining, redeployment to other sites, greater redundancy pay-outs and higher pay.

"We are entitled to it, it's about our dignity and respect. It's justice," she said. "Even with closure we are still fighting for permanent positions."

The closure of the Hume site and loss of 700 jobs is the latest blow to Broadmeadows which has suffered from the closure of the car industry and decline of manufacturing.

Unemployment in the suburb is the highest in the state at 25.3 per cent, according to federal government data released this year.

Mr Mujkic said if strikes went ahead it would be the largest industrial action involving the union for decades. The NUW has also reapplied for an industrial action ballot at an important tomato supplier to Woolworths and Coles, Perfection Fresh in South Australia.

The union's national president Caterina Cinanni said negotiations had stalled after more than six months of talks. It could be the first major farm strike in decades. Ms Cinanni said workers at the site wanted more secure jobs and fair pay rises.

Industrial action, particularly in the private sector, has become increasingly rare aided by declining union membership.

Working days lost, per 1000 employees, has more than halved compared to five years ago, Bureau of Statistics data shows. The level of strikes overall is at minuscule levels when compared to the 1970s and 1980s.