GENEVA (AFP) - China has accused United Nations human rights chief Michelle Bachelet of inappropriate interference in the country's affairs after she called for investigations into alleged excessive use of force by the police in Hong Kong.

China's mission to the UN in Geneva said an op-ed written by Ms Bachelet in the South China Morning Post was erroneous and "violates the purposes and principles of the Charter of the United Nations".

The article contains "inappropriate comments on the situation of the Hong Kong Special Administrative Region...(and) interferes in China's internal affairs", said the Chinese mission's statement.

It added that China had "lodged strong representations" with the UN rights office in Geneva.

In the article published earlier on Saturday (Nov 30), Ms Bachelet urged the authorities in Hong Kong to conduct "a proper independent and impartial judge-led investigation into reports of excessive use of force by the police".

Hong Kong's months-long protests started over a now-withdrawn extradition Bill that would send suspects to mainland China for trials but have since evolved into other demands including an independent inquiry into police behaviour during clashes with protesters as well as universal suffrage.

The unrest has also been fuelled by seething anger over China's perceived erosion of liberties in the semi-autonomous city.

Beijing denies stamping out Hong Kong's liberties and has portrayed the protests as a foreign-backed "colour revolution" aimed at destabilising mainland China.

China's mission to the UN said Ms Bachelet's article "will only embolden the rioters to conduct more severe radical violence".