"Current market conditions are clearly unfavourable," Pastor noted during a press conference in Madrid.

Given gloomy economic conditions, especially in Europe, there was little chance of attracting a large number of bids for the airports, the transport minister acknowledged.

That would in turn cut the chances of getting strong offers.

The previous Spanish government sought last year to sell 90.05 percent of the shares in airports in Madrid and Barcelona, aiming to raise 5.3 billion euros ($6.9 billion).

The mooted plan also included the sale of a 49 percent stake in the airport management group Aena, but was abandoned as legislative elections approached on November 20.

Groups that had expressed interest in the sale included the Spanish company Ferrovial, which owns the British airport operator BAA, in addition to European rivals Aeroports de Paris (ADP) and Frankfurt-based Fraport.

Meanwhile, Pastor announced the launch of a "new model of airport management" that sought to transform Aena into a "world leader in the airport and aerial navigation sector."

That plan allowed for future inclusion of private investors, she said, without providing details.

Spain's new centre-right government has already unveiled spending cuts of 8.9 billion euros and tax increases to bring in 6.3 billion euros, to reduce a swollen public deficit and ensure the country does not get dragged into the debt crisis mire that has already forced Greece, Ireland and Portugal to seek financial bailouts.

The transport ministry's 2012 budget has been cut by 15 percent to 1.6 billion euros.