Donations, supplies and condolences rolled in from Hong Kong, Macao and Taiwan for Central China's Henan province, after a massive flood that left at least 56 dead and affected millions.

Since the downpour began on Tuesday, about HK$100 million ($12.9 million) has been raised via campaigns by different groups in Hong Kong.

The money will be sent to Henan authorities via the Liaison Office of the Central People's Government in Hong Kong Special Administrative Region.

The Disaster Relief Fund Advisory Committee, which is dedicated to disaster relief outside Hong Kong, contacted the relief agencies to offer help.

Last year, it approved HK$1.1 million in grants for flood victims in Guangxi Zhuang autonomous region and HK$1.65 million for Jiangxi province in June and September, respectively.

In a social media post, Hong Kong Chief Executive Carrie Lam Cheng Yuet-ngor extended her deepest condolences to the people of Henan.

Because of the all-out efforts of the central, provincial and municipal governments, affected residents will be properly cared for, she said.

Lam said the increasing frequency of natural disasters has reminded Hong Kong to promptly respond to extreme weather caused by climate change.

Hong Kong's deputies to the National People's Congress and Chinese People's Political Consultative Conference－the national legislative body and political advisory body－also expressed condolences to their counterparts in Henan, and donated more than HK$5.6 million.

"The situation in Henan tugs at the heartstrings of compatriots in Hong Kong and Macao. We must offer assistance," said Irons Sze Wing-wai, Hong Kong member of the Chinese People's Political Consultative Conference's National Committee.

The Hong Kong Henan Association has distributed 500 boxes of mineral water, instant noodles, and other supplies to victims in the worst-hit areas through its two liaison offices in Henan's provincial capital, Zhengzhou.

In a letter to Henan governor, Wang Kai, Macao Chief Executive, Ho Iat-seng, expressed sincere condolences to the victims of the record-breaking rainfall and floods.

Ho called on Macao to support Henan. Macao's Henry Fok Foundation has donated 10 million yuan ($1.5 million) for disaster relief and post-disaster recovery.

Zhu Fenglian, a spokesperson for the Taiwan Affairs Office of the State Council, thanked the Taiwan community on Thursday for their support.

Food manufacturer Want Want and electronics manufacturer Foxconn, businesses with close ties to the mainland, were among those making donations. Foxconn, which is providing 100 million yuan in disaster relief funds, said its three factories in Zhengzhou were operating normally and the 350,000 workers were safe.

Many celebrities from Hong Kong, Macao, and Taiwan have also chipped in to help the flood-stricken province, expressing their condolences to those affected.