Airports in Belfast and Cardiff have been put up for sale by their Spanish owner.

Barcelona-based infrastructure firm Abertis said it was reviewing its 29-strong airport division which owns Belfast International and Cardiff airports.

It also operates Luton Airport under a long-term contract.

A spokesman for Abertis, which also has airports in Mexico, America and Sweden, said: "We have started a process of reviewing our airport division, including the possibility of a future sale of the division."

He said Abertis, which is listed on the Spanish stock exchange and also manages toll roads and telecommunications infrastructure, had appointed Citi and AZ Capital to look into the future of the division.

The Spanish group, which made profits of €720m in 2011, has seen passenger traffic hit by the economic woes of the country.

The possible sale comes after the recent lucrative sell-off of Stansted and Edinburgh airports by Heathrow Airport Holdings - formally BAA - in the wake of a Competition Commission ruling.

The Welsh government has already said it is looking at buying Cardiff airport, and it is thought to be close to a deal.

The airport has seen passenger numbers halve since 2007, falling to one million last year.

The potential sale of Luton Airport comes after a dispute between Abertis and the town's council.

Luton Borough Council, which owns the airport, threatened to end Abertis' contract - which runs until 2031 - in a dispute over its vision for developing the airport.

But the two sides agreed a £100m revamp of the airport last August.

Abertis acquired Belfast International Airport, which deals with around 12 million passengers a year, through its company TBI in 1996.