Finland’s Neste Oil said it had lowered output at its refinery in Porvoo due to damage at one of the site’s hydrogen plants, adding that the problem would not be fixed for several weeks.

Neste oil products head Matti Lehmus said the damage will have an impact on the refinery’s diesel and gasoline production, but declined to give specific details.

“We will evaluate the schedule of the repairs as well as the estimated financial impact within two weeks,” he said. He added that another hydrogen plant was online at the site.

“This is of course a negative thing, it will cut their output... The scale of the impact is as yet difficult to estimate,” said Evli analyst Markku Jarvinen.

Analysts had cut their estimates for the company after it said earlier this month 2014 operating profit was expected only to hit the lower end of its previously stated guidance range of 450 million euros ($600 million), plus or minus 10 per cent.

“It is a temporary, technical problem, but such problems could mean they will have to check again if the (2014) guidance is still in place,” Jarvinen said.

The Porvoo refinery in southern Finland has four production lines with total refining capacity of about 200,000 barrels per day. Neste said the incident was not expected to harm deliveries that have already been contracted.