Algeria plans to increase natural gas output by 13 percent by 2019, the energy ministry said, to reverse a decline in energy production in recent years that has hit its export earnings and spending policy.

Investment to increase its gas output was estimated at $40 billion, it said in the latest edition of its inhouse magazine Algeria Energy. The article gave few details on how or where it would increase output.

An OPEC member and a major gas supplier to Europe, Algeria relies heavily on energy revenues, which make up 60 percent of its budget and account for 95 percent of its exports.

On Saturday, Prime Minister Abdelmalek Sellal said the government will cut spending by 9 percent in 2016 due to a decline in earnings after the drop in global crude oil prices. [ID:nL5N1140IZ]

Earnings from oil and gas exports are expected to fall 50 percent to $34 billion this year.

The government earlier this month said oil and gas export volumes dropped 8.9 percent in the first quarter of 2015.

That followed a report by the country's National Statistics Bureau that oil and gas production has been in decline since 2016.

State energy firm Sonatrach had said it would stick to a $90 billion five-year investment plan despite the decline in crude prices. But it has yet to give details of a new energy bidding round to try to draw in foreign oil investors.