Algerian state energy company Sonatrach plans to intensify exploration by drilling 125 wells a year with a target of increasing production to 225 million tonnes of oil equivalent by 2019, it said on Sunday.

The North African OPEC state is looking to increase crude and gas production that has stagnated over the past three years because of a lack of foreign investor interest in Algeria's energy because of unattractive terms.

Speaking at a North Africa oil and gas conference in Algiers, Sonatrach's interim chief Said Sahnoun said that the company would invest about $80 billion between next year and 2019 to boost production and does not expect lower oil prices to affect spending plans.

"I remain optimistic about our energy output for the coming years, and we are ready to work with all of our partners," he said.

Algeria supplies about a fifth of Europe's gas needs but relies on mature fields for most of its energy output and looks to foreign explorers to help to develop new reserves and increase flagging production.

Last year total production was at 192 million tonnes of oil equivalent, including 121 million tonnes from natural gas, 54.5 million tonnes from crude oil and 9.5 million tonnes from condensate.

The Sonatrach chief did not give any detail on proposals Algeria will make to improve terms, such as changes to the hydrocarbons law, to draw in foreign companies after the last energy bidding round failed to attract many investors.

Only four of 31 areas on offer were taken by foreign consortiums that included Spain's Repsol, Royal Dutch Shell and Norway's Statoil. It was Algeria's first attempt to draw investors since a disappointing 2011 round.