Algeria's Tiguentourine gas plant is ready to come fully back online for the first time since a deadly militant attack in 2013, general manager Kamel Aoues said on Saturday.

"Full production is for the coming days, all tests have been passed successfully," Aoues told Reuters during a press visit to the site.

The plant, 1,600 km (995 miles) south east of the capital Algiers, is operated by Algerian state energy firm Sonatrach, BP and Statoil.

Current production is estimated at 16 million cubic metres per day, and should reach 24 million to 25 million cubic metres when the third and final section of the plant comes online, plant managers said.

Algeria is a top gas supplier to Europe. Its economy is heavily dependent on hydrocarbons exports, and the OPEC member has been struggling to boost production to offset the fall in oil prices.

A source who asked not to be named said the return to full production would coincide with a ceremony at Tiguentourine on August 1 attended by Energy Minister Nouredine Bouterfa and Sonatrach chief executive Amine Mazouzi.

In January 2013, 40 mostly foreign oil contractors were killed after Al Qaeda militants attacked the plant and took dozens of workers hostage.

Currently, about 20 percent of the 500 employees at the plant are foreigners. The cost of repairing the plant was estimated at $90 million, Aoues said.

Security is handled entirely by the military, which has a visible presence around the site. Several check points have to be crossed to reach the plant.

"I have been in the plant for the past two months, it is quiet and safe," security contractor Robert Sherman told Reuters during a tour around the site.

Algeria has become a key regional security partner for the West after largely shaking off an Islamist insurgency that began in the 1990s.

However, security in the southern desert regions has been threatened by regional instability, especially in Libya, which is just 40 km from the Tiguentourine plant. - Reuters