The Tokyo government urged residents on Wednesday to refrain from joining parties at parks during the famed cherry blossom season, in the latest disruption caused by concerns over the new coronavirus.

The season, which is expected to start in mid-March, is traditionally celebrated with hanami -- or viewing parties -- in cherry blossom hotspots, with picnics organised beneath the trees.

The metropolitan government said such events have risks of spreading the virus, which has at least infected 284 people in Japan.

"It is expected to be crowded at parks and near rivers managed by the Tokyo government during the cherry blossom season," the government said in a statement. 

"Please refrain from joining parties that involve food and drinks in order to prevent the spread of the new coronavirus infections."

They said walking to enjoy sakura, or cherry blossom is fine but advised people to wear masks if they are coughing.

The affected areas include famous parks in Ueno and Yoyogi and also Sumida river.

Japanese Prime Minister Shinzo Abe has stepped up measures to contain the virus, urging schools to close for several weeks and calling on organisers of large events to consider cancelling or delay.

Everything from football matches and music concerts have been affected, while sport's spring sumo tournament will be held behind closed doors.

Japan's cherry blossom season is feverishly anticipated by locals and visitors alike. Many tourists plan their entire trips around the blooms, and Japanese flock to parks in their millions to enjoy the spectacle.

Cherry blossoms symbolise the fragility of life in Japanese culture as full blooms only last about a week before the petals start falling off trees.

Weathernews, a weather forecasting firm near Tokyo, predicts the blooming will start on March 17 in Tokyo.