A cargo plane has skidded off a Hong Kong runway and ended up in the sea, killing two people.

The Boeing 747, flown by Turkey’s ACT Airlines, was landing at Hong Kong International Airport about 3.50am (6.50am AEDT) on arrival from Dubai, United Arab Emirates, authorities said on Monday.

The airline had leased the aircraft from Emirates, a long-haul carrier based in Dubai.

Four crew on the plane were rescued and taken to a hospital.

Authorities said two people in an airport ground handling vehicle, which had fallen into the sea, were killed.

Emirates said the Boeing 747 freighter flying as EK9788 was wet leased and operated by ACT Airlines. In wet leases, the company supplying the plane also provides the crew, maintenance and insurance. Emirates said there was no cargo on board.

Local Hong Kong broadcasters showed the aircraft partially submerged just off the edge of the airport’s sea wall.

The aircraft’s front half and cockpit were visible above water but the tail end appearing to have broken off.

Two boats, possibly carrying rescuers, were shown near the aircraft.

The crash occurred on the north runway of Hong Kong International Airport, one of Asia’s busiest. It remained closed, while the airport’s two other runways continue to operate.

The airport was built on reclaimed land by merging two smaller islands north of Hong Kong’s Lantau Island in the South China Sea, at the mouth of the Pearl River.

The edge of the north runway lies only a few hundred metres from the water, while the other two runways are even closer.

Hong Kong’s Civil Aviation Department said it was following up with the airlines and other parties involved in the crash.

Emirates is known for its passenger flights coming out of Dubai International Airport, the world’s busiest for international travel.

However, it also operates a thriving cargo business out of Al Maktoum International Airport at Dubai World Central, the sheikhdom’s second airport where it plans a $US35 billion ($A54 billion) improvement over the coming decade. The ACT Airlines’ flight had taken off from Al Maktoum, known as DWC.

Emirates, owned by a sovereign wealth fund in the city-state, noted in its most-recent annual report that it had added two wet-leased Boeing 747s “to serve surging customer demand”.

Emirates has some 260 aircraft in its fleet, the majority either Boeing 777s or double-decker Airbus A380s.