Police have urged people to use public transport on Sunday as road closures due to a large-scale running event are expected to cause traffic congestion.

Organisers of the Standard Chartered Hong Kong Marathon said 74,000 runners are expected to take part in the event.

The marathon and half-marathon will both start from Nathan Road in Tsim Sha Tsui - at 6am and 5.40am respectively - while the 10km race will start from the Island Eastern Corridor. All races will finish at Victoria Park.

Officials said roads will be closed in phases from 11.30pm on Saturday, including various sections of Western Harbour Crossing, Tuen Mun Road, Nathan Road and Lung Wo Road.

Senior Transport Officer Ann Wong said traffic would be heavy in various areas on Sunday.

"As there will be many temporary road closures in different parts of Hong Kong on Sunday, the Transport Department expects traffic near the affected area to be very busy. Drivers should avoid going to the affected places," she said.

"The public should plan ahead and use alternative roads to prevent delays. They should use public transportation, especially railway services."

Eight MTR lines will start earlier to accommodate runners, with the first train on the Tuen Ma and Tung Chung lines leaving at 3:25am.

Roads will be reopened in phases after the races.