The operator of the Indonesian capital's main airport has apologized to passengers for flooding at its brand new terminal.

Rains overcame drainage pipes and inundated the arrivals area on Sunday.

The $560 million terminal opened last week to domestic flights by national carrier Garuda but has been plagued by complaints about its lack of readiness.

The airport operator and government hope the new terminal, and a third runway that is under development, will relieve over-crowding and make Jakarta a rival to Singapore and Bangkok for international stopovers in Southeast Asia.

PT Angkasa Pura II, the airport operator, said it is investigating the cause of the flooding.

Local media said drains might have been clogged by construction debris.