Striking Coles warehouse workers have been threatened with legal action by the company that manages the Melbourne site.
About 80 workers picketed the gates of the key Coles warehouse in the city's north overnight with numbers swelling to 200 on Wednesday morning.
The warehouse's 600 workers stopped work from 6am (AEST) on Tuesday, preventing goods going in or out.
Toll, which manages staff at the Somerton warehouse on behalf of Coles, says the company respects the right of workers to take the protected action.
However, Toll spokesman Chris Whitefield says the company will not tolerate "illegal action" such as blocking staff and vehicles from entering or exiting the facility.
"We will not tolerate illegal blockading and intimidation," he said in a statement.
"We will be assessing all options in terms of legal action against those participating in this unlawful behaviour."
Mr Whitefield said negotiations with the union were continuing but would not confirm Toll was meeting with the National Union of Workers (NUW) on Wednesday to try and resolve the dispute.
The workers have vowed to strike until they are granted the same shift penalty and RDO entitlements they say workers at other Coles warehouses receive.
The strike has raised concerns supply to Coles stores will be disrupted but Coles spokesman Jim Cooper said the impact would be minimal.