COPENHAGEN, March 22 (Reuters) - Finnish forestry firm Stora Enso on Friday said it would start fully ramping down its Imatra and Oulu mills on Sunday due to ongoing political strikes that are hitting ports and transportation in Finland.

Stora Enso had already begun ramping down some production lines at Imatra, but will start shutting down the rest on Sunday, a company spokesperson said.

The company expects its Oulu and Imatra mills to be fully closed by the beginning of Easter, the spokesperson said, adding that it would take a few days to fully close all production lines.

"Once we hear more about the strikes, if they will be ending by April 1, as we have now been informed, or whether they will go on, then we have to make a new assessment at that time," the spokesperson said.

Strikes on the Finnish railways were limiting the supply of wood to the two sites, the spokesperson said. "The other reason is that the warehouses are now just filling up so there's no place to store the finished goods," she added.

Stora Enso earlier this week shut down its Varkaus packaging board mill. It also stopped paper production at its Anjalankoski mill, but continues board production at the site, the spokesperson said.

Several companies including steelmaker SSAB, refiner Neste and forestry group UPM have said their operations are negatively impacted by the strike. (Reporting by Louise Breusch Rasmussen, editing by Stine Jacobsen)