A former editor of a Hong Kong newspaper whose abrupt dismissal in January sparked protests over press freedom is in critical condition after being hacked by an assailant with a meat cleaver, according to Hong Kong police.

A man wearing a motorcycle helmet "suddenly" attacked Kevin Lau Chun-to on Wednesday morning and then fled on a motorcycle driven by another man, the Associated Press news agency reported.

Lau was conscious but in critical condition when he was taken to hospital.

Police said they were investigating but did not say why he was attacked.

Lau was named editor of the respected Ming Pao newspaper in 2012 but was replaced last month by Malaysian journalist Chong Tien-siong, according to the South China Morning Post newspaper.

The move raised fears among journalists that the paper's owners were moving to curb aggressive reporting on human rights and corruption in China.

Lau's dismissal and other cases have raised press freedom concerns in the semi-autonomous Chinese city.

Lau's wife, Vivien Chan Pik-kwan, confirmed the attack over the phone.

"Police told me that he suffered three knife wounds in the back and leg," she told the South China Morning Post

According to witnesses who live in the Lei King Wan area where the attack took place, such occurrences are very rare in the area.

A Hong Kong Journalists Association official statement expressed shock and outrage: “Journalists consider the incident a serious provocation to the Hong Kong press and freedom of expression.”

Leung Chun-ying, Hong Kong's chief executive, and two ministers "strongly condemned' the assault.

In a media statement, Leung said: "The SAR government and myself are very concerned about the incident, feel indignant about such act of violence, and we strongly reprimand it.

"Hong Kong is a society of the rule of law, and we are absolutely intolerant about violence of this kind. The police will investigate comprehensively, and I also call on [residents] to provide information to the police on this case immediately, so that we can arrest the culprit responsible."

Source: AP And South China Morning Post