Spain's national carrier Iberia said it was considering charging passengers for check-in baggage.

"It is being studied, but we don't know if it will affect all passengers or when it will be implemented," an Iberia spokeswoman said.

The newspaper El Mundo quoted an internal Iberia document as saying that the airline plans to charge passengers less that 15 euros to register their first check-in bag starting October 20.

Charging for check-in luggage is something traditionally done by budget airlines.

"A lot of travelers want to travel at very low cost, and one way to achieve that is to split up the product," the spokeswoman said.

Iberia, which began merger talks with British Airways last year, has been hard hit by the economic crisis and is faced with stiff competition from budget airlines in its domestic market.

Two Spanish consumer association, Facua and UCE, threatened to take legal action against Iberia over the plan.

They said laws governing air transportation in Spain mandate that the price of a ticket includes the passenger and their baggage, as long as the weight is not excessive.

Facua filed suit earlier this year against 16 budget airlines, including easyJet and Ryanair, which charge passengers for check-in bags.