Nissan's car making plant in Barcelona, Spain, must improve productivity if it wants the Japanese parent company to continue investing in the facility, Nissan chief executive Carlos Ghosn said during celebrations to mark the division's 25th anniversary.

Ghosn's remarks were a gloomy reminder that Nissan could shift production from Spain to more "efficient" plants in Thailand, Egypt or the UK, something it considered doing last May before striking a new labour deal that improved flexibility.

The 4,000-worker factory has made "an important improvement" in the last three years but "it must maintain high competitive standards," Ghosn said.

Jordi Carmona, Nissa secretary general at trade union UGT, said he was not worried about Nissan moving output from Barcelona because the new labour contract "provides significant efficiencies."

However, he said unions would welcome negotiations to boost the site's competitiveness. Two ways to do this would be to prolong weekend shifts and introduce a so-called 'vacation corridor' to enable the factory to stay open during the 30-day August summer break.

To further boost efficiency, the plant should increasingly specialise in building commercial vehicles, a move that would help it stand out from Nissan's more competitive car-making factories, Carmona said.

Nissan is on track to meet its target of raising Barcelona's output 38% to more than 170,000 vehicles this year, Carmona added. There, the company makes the Renault Trafic, Opel Vivaro and Nissan PrimaStar light vans as well as the Pathfinder SUV, Navara pickup truck and Tino minivan.

Ghosn said the Renault-Nissan manufacturing joint venture is going well and that it should continue to bring future synergies between the companies.

Ivan Castano