Repsol YPF, the Spanish oil company, has refuted reports that it asked its adviser Merrill Lynch to buy shares in Gas Natural, the company at the centre of a takeover row in Spain.

Merrill bought 712,220 shares in Gas Natural, which has made a €26bn ($29bn) offer for energy group Iberdrola, in the past two trading days, a move that the Spanish press suggested was on Repsol's behalf. Repsol has opposed the bid for Iberdrola, saying the timing was wrong, that any takeover should be friendly and that the regulatory elements had not been considered thoroughly enough.