Dozens of workers have walked out of a factory where they spent four days holed up in the lunchroom as part of a heated industrial dispute.

More than 25 employees at International Flavours and Fragrances (IFF), which makes flavourings for companies including Coca-Cola and Smiths Chips, staged a sit-in protest at their Dandenong South plant since negotiations for a new workplace deal broke down on Tuesday.

Workers protest from inside the lunchroom at the Dandenong factory.

The workers voted to leave the factory on Friday evening, claiming a "significant win" after the company agreed to bring its Asia-Pacific management team to the negotiating table.

A petition calling for the regional managers to meet with employees had attracted more than 1000 signatures.