The Penang International Airport is so congested that some have described it as an 'international pasar malam' (night market), said Chief Minister Lim Guan Eng.

He urged the federal government to speed up the airport's expansion, which would increase the annual passenger capacity to 10 million.

The airport, located in Bayan Lepas, reached its annual capacity of 6.5 million five years ago, instead of 2020 as planned, he said.

"The written parliamentary answer to my question in May by Transport Minister Liow Tiong Lai is that a project to expand the airport from 6.5 million to 10 million capacity has been proposed under the 11th Malaysia Plan," said Lim.

"That it is now being considered by the Economic Planning Unit under the Prime Minister's Department."

The Penang International Airport made headlines last month when it was flooded after a downpour on the island.

The airport was recently given a makeover with more space for eateries and souvenir shops, but remains congested due to the high number of tourists.

Lim said there was no plan to upgrade the Penang airport other than the carpark project slated for next year.

A five-storey building with the capacity of holding 3,300 cars will be built in two phases, Lim said.

Each phase is supposed to take two years to complete, while the entire cost of the building is estimated at RM80 million, he said.

"The failure to expand the airport will not only jeorpadise the inflow of foreign tourists but will bring negative impact to Malaysia Airports Bhd's (MAB) income," said the DAP secretary-general.

"Penang airport is most profitable for MAB after KLIA and KLIA2, it is both in the public and national interest to expand the Penang airport as soon as possible."