Buenos Aires - Argentina's National Congress approved the renationalization of the financially troubled airline Aerolineas Argentinas, which had been privatized 18 years ago, and its regional subsidiary Austral.

The Senate approved the measure Wednesday by a 46-21 vote after the Chamber of Deputies had also passed it.

Debt-laden Aerolineas has been in crisis for years, and state aid was seen necessary for it to avoid collapse. Delays are a daily occurrence, and many travellers try to avoid taking its flights.

The Chamber of Deputies made considerable changes to the legislation that the Senate must yet approve, and both houses must also still vote on the sale price for the airline, which has yet to be negotiated with the Spanish travel conglomerate Grupo Marsans.

Among the changes to the legislation was a ban on another privatization of Aerolineas.

Resistance was strong among lawmakers to a potential assumption of Aerolineas' 890 million dollars in debt, which the Argentine government agreed to in principle in mid-July in a deal to buy all of Marsans' shares in Aerolineas and Austral.

Marsans holds 94.91 per cent of Aerolineas' stocks and 97 per cent of Austral's.

The Spanish company warned it would fight with all means at its disposal against demands for an expropriation of the airlines by some sectors in Argentine society.

The two airlines control 80 per cent of the domestic air passenger market. However, about half their planes are grounded because they are missing parts.

Aerolineas was founded in 1950 and remained a state company until 1990. Then-president Carlos Menem sold Aerolineas to the Spanish airline Iberia, and Marsans has operated it since 2001.

Many Argentines have accused the Spanish of ruining the company. (dpa)