At least four people were killed when a fire engulfed several high-rise blocks in a Hong Kong residential estate on Wednesday, the government said, with media reporting that some residents were trapped inside.

Massive flames took hold on the bamboo scaffolding on at least three apartment blocks at Wang Fuk Court in Tai Po, a district in the northern part of the Chinese financial hub, before spreading to other parts of the buildings.

"Four people are certified dead, two are in critical condition and one in stable condition," by 5:00 pm (0900 GMT), according to a representative from the government's Information Services Department.

One of the dead was a firefighter, according to Hong Kong media.

At least one man and one woman were unconscious to hospital with severe burns, while police earlier received reports of trapped residents, media reports said.

Thick plumes of smoke were seen billowing from the construction scaffolding on multiple towers, live broadcast footage showed.

Authorities declared a four-alarm fire -- the second highest level.

Sections of a nearby highway were also closed by the firefighting operation.

"Residents nearby are advised to stay indoors, close their doors and windows, and stay calm," the Fire Services Department said.

"Members of the public are also advised to avoid going to the area affected by the fire."

Four people were hospitalised after a separate fire on the scaffolding of a building in Hong Kong's central business district last month.