In the run-up to the end of a two-week garment worker strike in Cambodia this week, a group of leading apparel brands joined together to call for "peaceful negotiations".

The seven brands - H&M, Gap, Inditex, Adidas, Puma, Levi Strauss & Co and Columbia Sportswear – wrote an open letter to the Cambodian government, manufacturers and trade unions.

In it, they called for the peaceful resolution to the dispute over minimum wage increases for garment workers, after escalating violence against protestors last week led to the deaths of at least four people.

Expressing their “deeply felt concern”, the companies said: “We strongly oppose all forms of violence.

“It is with great concern that we have observed both the widespread civil unrest and the government’s use of deadly force.”

Highlighting their concerns for the security and safety of workers employed by their suppliers, and the long-term stability of the Cambodian garment industry, the seven wrote: “Given the reported deaths and injuries of 3 January 2014, we call on all parties to exercise maximum restraint and refrain from the use of force or violence.”

The seven brands also called on the Cambodian government, GMAC and its members to support the development of a regular wage review system.

Demonstrations on the streets ended earlier this week, according to Ken Loo, secretary general at the Garment Manufacturers Association in Cambodia (GMAC), with most factories having already resumed their operations.

The Labour Advisory Committee on 24 December proposed to double the minimum wage for textile, garment and footwear factory workers from the current level of US$80 per month to $160 per month over the next five years.

Trade unions, however, are urging for the minimum level to be raised to $160 immediately. 

The dispute raises questions about the future stability and competitiveness of the Cambodian garment sector. The country’s largest industry employs about 400,000 people and earns some $5bn a year in export revenues.