MADRID, Oct 6, 2008 (AFP) - The tie-up between British Airways and Spanish national carrier Iberia will take longer than expected due to the downturn in the aviation sector, BA president Willie Walsh said in an interview published Monday.

'I can say that the merger will take longer than expected. Especially due to the problems of the sector which have forced us to focus more on our business than in the deal,' he said, in comments quoted by the Spanish daily newspaper El Mundo. It did not cite further details.

When the two airlines announced their plan to merge at the end of July, creating the world's third-biggest carrier by revenue, Iberia president Fernando Conte said he expected the operation would take several months.

Global air traffic has continued to decline as the sector endures a 'perfect storm' of rising fuel costs and the global financial crisis, the International Air Transport Association (IATA) said last week.

BA said Friday that in September its load factor -- a measure of how well it fills its planes -- was down 4.3 percentage points at 74 percent and it warned that it risked failing to meet its full-year revenue forecasts.

The airline said its more profitable long-haul premium traffic -- which includes the key London-New York corporate routes -- had softened since the middle of the year and forward bookings had been hit by the economic downturn.

Asked whether BA was interested in Italian flagship Alitalia, Walsh said: 'If they do not restructure their business, no. If they survive, we would like to establish a relationship.'

'This does not have to be through an investment. Maybe we can form an alliance. But only if there is a restructuring,' he added.

The Italian government has frequently mentioned BA as a possible stakeholder in the new Alitalia.