Workers at French oil major Total SA's (TOT) Gonfreville refinery are planning a strike April 9 to protest against the company's plans for an overhaul of the unit, a CGT union official said Friday.

The strike could reduce the refinery's processing of oil that day, the official said, adding that the action would also aim to disrupt the transportation of products leaving the site.

The strike is set to last 24 hours and would begin with workers on the morning shift, the official said.

-By Adam Mitchell, Dow Jones Newswires, +33 1 40171756; adam.mitchell@dowjones.com