Brussels airport scheduled nearly 40 flights on Monday, officials said, as Belgium struggles to get back to normal after two suicide bombers blew themselves up in the departure hall nearly two weeks ago.

The number was a sharp rise over the three flights at Belgium's main air hub on Sunday, but a far cry from the 600 the airport usually handles per day, officials said.

"Some 39 passenger flights, most of them arriving from or departing to European cities, are planned," Brussels Airlines spokesman Kim Daenen told AFP, adding her company was the only operator on Monday.

On Tuesday, the airline will run 89 flights, with 48 heading to European destinations, five to Africa and one to New York. Some 40 return flights are planned.

Brussels airport spokeswoman Florence Mulls said other companies such as Dutch carrier KLM will operate from Wednesday.

The airport reopened on Sunday for the first time since two Islamic State commandos blew themselves up in the departure hall on March 22 in coordinated blasts that also struck a metro station in the Belgian capital, killing a total of 32 people.

Brussels Airlines planes flew on Sunday to the Portuguese city of Faro, then Athens and Turin before all three returned, officials said.

Two big white tents now serve as temporary check-in facilities and passengers were asked to come three hours before departure to allow time for tight new security checks.

There was also a strong security presence inside the tents where passengers walked through metal detectors and had their bags screened before checking in and being allowed to enter the main building.

Under the new system, only passengers with travel and ID documents are allowed into the makeshift departure hall, and all bags will be checked before entering. Once inside, travellers will still have to go through the usual security barriers.

The airport will initially only be accessible by car, with no access for buses and trains. Vehicles will be screened and subject to spot checks.

It will take months to repair the departure hall, according to airport chief executive Arnaud Feist.

The damage from the blasts was severe, with pictures from the scene showing the building's glass-fronted facade in shatters, collapsed ceilings and destroyed check-in desks.

Feist said he expected the airport to start running normally again from late June or early July.

Brussels airport, which claims to contribute some €3bn ($3.4bn) annually to the Belgian economy, has not released any figures on the economic impact of the shutdown, but Brussels Airlines has said it was losing €5mn daily.