Two people were killed and two others injured in a fire at a Libyan fertiliser complex in which Norway's Yara International holds a 50% stake, Yara and Libyan state energy firm NOC said on Tuesday.

The fire on Sunday broke out during maintenance work on a heat exchanger at the complex in the city of El Brega, NOC said in a statement on its Internet site. 

"The other plants of the complex have not been affected by the incident and continue to operate normally," it said.

Torgeir Kvidal, a spokesman for Yara, confirmed that two people had been killed at the plant and two injured. Asked when production would restart at the unit he said: "I do not expect any long stoppage, but it is too early to be very precise."

Early last year Yara sealed a joint venture deal worth $225 million with Libya to upgrade the complex, which produces urea and ammonia.

Libya's National Oil Corporation (NOC) and the Libyan Investment Authority each retain 25% of the company, named Libyan Norwegian Fertiliser Company (Lifeco).

At the time the joint venture deal was finalised, the El Brega complex produced 700,000 tons of ammonia per year and around 900,000 tons of urea, Yara said in a statement.