A merger between Malaysia Airlines (MAS) and AirAsia is unhealthy for the domestic industry and hence is not possible, MAS Chief Executive Officer Christoph Mueller said Thursday.

"I am a strict opponent to this, I would absolutely advocate for each country to have two carriers," he said.

Monopoly is not good for consumers, particularly domestic consumers, he said at the Global Airport Developments (GAD) Asia 2015 conference, Thursday.

From a macroeconomic perspective, two carriers would help keep air fares lower, he said when asked about a possible merger between the two airlines after a previous arrangement fell through.

In August 2011, MAS and AirAsia entered into a collaboration agreement, in conjunction with a share swap deal, to work together and not to compete against each other, but the deal was aborted eight months later after complaints from the public.

AirAsia Group Chief Executive Officer Tan Sri Tony Fernandes recently said AirAsia had entered into discussions with MAS over possible cooperation in the maintenance, repair and overhaul sector.

"If prices from Kuala Lumpur to Kota Kinabalu or Kuching are subjected to a monopoly situation, it is not good for both the economy and country," he said.

The three-day conference which ended today aimed to explore strategies for airport development and finance in high-growth markets.