UK trade union Unite is to step up its campaign for workers in Marks & Spencer's meat supply chain with international and national demonstrations outside the retailer's outlets.

Demonstrations will take place in Northern Ireland, Turkey and Hungary, Unite said, followed by action next week in the Republic of Ireland, Korea, Romania, Poland and Bermuda.

This latest action follows last month's demonstrations across the UK where activists were demanding the group operates an "ethical supply chain".

"This is not just about workers in the UK and Republic of Ireland this is a global organising strategy," said Unite joint general secretary, Tony Woodley. "Justice for low-paid workers is the least we should expect from a brand that claims to have corporate social responsibility at the top of its agenda. The workers expect it, the union expects it and M&S customers expect it. It is time M&S delivered."

The union claims a "permanent two-tier workforce" among many suppliers has been created, where migrant agency workers are on lower pay and conditions than directly employed staff.

A spokesperson for Marks & Spencer, said: "We are extremely disappointed with the action Unite is taking as we met with Jack Dromey just two weeks ago to discuss this issue, and have always had regular and constructive dialogue with Unite.

"We are at a loss as to understand why they continue to single out M&S when we have a leading position in labour standards and work very hard with all our suppliers to maintain these high standards."