Polish gas monopoly PGNiG said on Monday it had doubled production of crude oil last year to about 1.1 million tonnes and raised output of natural gas to 4.6 billion cubic meters from 4.3 billion in 2012.

In the fourth quarter alone, crude production amounted to 310,000 tonnes, compared with 139,000 a year earlier, it said.

The jump was due to the opening of the Lubiatow oil and gas rig, the biggest in Poland, and the start of operations in Norway by PGNiG Upstream International.

The company said it would release final estimates of its oil and gas output on March 5 together with its financial results.