Criteria, which is the main shareholder in lender Caixabank, owns a 26.7% stake in Naturgy. GIP and CVC each own around 20%.

TAQA said it is in talks with CVC and GIP regarding the possible acquisition of their shares, adding that if such an acquisition were to take place, a takeover bid would have to be made for the entire capital of Naturgy.

It is also in talks with Criteria over a possible partnership agreement. No agreement has been reached with Criteria Caixa, CVC or GIP, it said.

(Reporting by Pietro Lombardi and Jesús Aguado, editing by Aislinn Laing)