BOSTON -- Former Vice-President Joe Biden has attended a rally of striking supermarket workers in New England.

Biden spoke Thursday at the gathering of unionized Stop & Shop employees outside a store in Boston's Dorchester neighbourhood.

Biden, mulling a run for the Democratic nomination for president, said workers at the supermarket chain are "not being treated across the board with dignity."

United Food and Commercial Workers union members at 240 Stop & Shop stores in Massachusetts, Rhode Island and Connecticut went on strike on April 11 to protest what they call cuts to health care and take-home pay in the company's latest contract proposal.

Stop & Shop, a division of Dutch company Ahold Delhaize, says it is offering across-the-board raises and "excellent" health care benefits that beat industry standards.