Lower output by the OPEC member and gas exporter adds to problems for its finances caused by low crude oil prices. Energy accounts for about 95 percent of the north African country’s exports.

It produced 38.1 million tonnes of oil equivalent in the first quarter, with foreign energy firms accounting for 33percent of the total, state radio said, without giving details.

An energy ministry source confirmed the figures were accurate.

BP, Statoil, Anadarko Petroleum Corp., Repsol and Total  are the main foreign energy firms in Algeria.

Algeria has struggled in recent years to attract foreign investment to its energy sector, where it needs help to bolster output at maturing fields.

Last year, Algeria awarded only four of 31 oil and gas blocks on offer to foreign consortiums.

That followed a disappointing auction in 2011 when Algeria secured bids for just two of 10 fields. Some foreign operators see Algeria's terms as unattractive.

It also wants to build five refineries to double output by2019, as it comes under pressure from growing domestic demand.

Refined oil products output fell 8.2 percent to 7 milliontonnes from 7.6 million in the first quarter, forcing the government to import 581,000 tonnes to meet domestic demand, state radio reported.

Petrochemical products output jumped by 82 percent to924,000 tonnes due mainly to higher ammonia and urea production.

Officials have said state-owned energy company Sonatrach will stick to its $90 billion five-year investment plan despite low oil prices.

It raised investment by 19 percent to $3.6 billion in the first quarter, state radio said.