Workers at Ford's Russian assembly plant are staging a go-slow strike in a dispute over wages, union and company officials reportedly said on Tuesday.

According to Reuters, the factory in St Petersburg, Russia's second city, was one of the first to be opened in the country by a foreign car maker and plans to turn out 36,000 Focus models this year. It is Ford's only plant in Russia.

"The go-slow strike has started. We are working strictly to rule, we are not exceeding our targets and therefore production levels at the factory have fallen," a member of the plant's strike committee told Reuters.

A spokeswoman for Ford's Russian operations, Yekaterina Kulinenko, told the news agency cars were still coming off the assembly line. She said she could not put a figure on how much the strike action would cost the company.

"Ford is ready to hold negotiations, and meetings with the unions continue. But strike action is not a constructive way of dealing with this dispute," Kulinenko reportedly said.