STOCKHOLM, Sweden (AP) _ A work slowdown by three unions that began two weeks ago may cut Volvo's auto production by 20 percent and will start hurting other manufacturers worse than expected, officials said Monday.

The unions, which represent 300,000 workers, began a comprehensive overtime ban on May 2, demanding better pay and working conditions.

The Swedish engineering managers association had projected the ban would cost all industries about 80 million kronor, or $11 million, a day.

``Probably this will increase in the days to come,'' said Kjell Treslow, spokesman for the Swedish Engineering Association.

Volvo said Monday the slowdown could reduce production by about 20 percent, or some 400 cars per week, the state news agency TT reported.

Other major companies affected include appliance maker Electrolux and Ericsson, a manufacturer of telecommunications equipment.

Negotiations were continuing, the news agency said.

The latest proposal by mediators would raise salaries 3 percent a year over three years. The head of the metal workers' union said the bid was unacceptable because it enabled employers to hire low-paid trainees for extended periods.