HONG KONG (AFP) - Hong Kong's leader on Tuesday (April 5) hit back at growing calls for independence from China, particularly among young activists, as he dismissed the need for any discussion on a breakaway.

Unpopular leader Leung Chun Ying's remarks come as concerns grow over increasing interference from Beijing in the semi-autonomous city's affairs, with fears that its cherished freedoms are ebbing away.

Since the failure of mass pro-democracy protests in 2014 to win political reform, young campaigners have spearheaded a "localist" movement, which seeks much more distance from China.

Last week saw the launch of the new pro-independence Hong Kong National Party, made up of 30 to 50 students and young professionals.

Localist activists have already made some inroads into mainstream politics, with one candidate taking more than 60,000 votes in a recent parliamentary by-election.

"There are people in society, including some young people, who have put forward whether or not Hong Kong interests have been influenced or even corroded by the mainland," Mr Leung told reporters.

"In fact, since this administration assumed office... we have, in each livelihood issue, aimed to put Hong Kongers first."

Mr Leung listed policies, including a ban on mainland mothers giving birth in Hong Kong and a special property duty for foreign buyers, as protecting local interests.

"We don't need to come to the point where we ask whether we need independence to safeguard the interests of Hong Kong people," he said.

He did not address freedom of speech or political reform, key issues for activists.

The Hong Kong government last week threatened to "take action" against the Hong Kong National Party, saying advocating independence was against the city's mini-constitution and would "undermine the stability and prosperity of Hong Kong".

It would not specify what shape that action would take and Mr Leung again evaded that question on Tuesday.

The new party says it has been banned from registering in Hong Kong, making it difficult for it to run in elections.

China has also slammed the group and voiced its "resolute opposition" to calls for independence.

Hong Kong's way of life is protected by a 50-year agreement signed when Britain handed the city back to China in 1997 and it enjoys freedoms unseen on the mainland.

But there are fears that those are being eroded after a string of troubling incidents.

The latest was the disappearance of five Hong Kong booksellers, known for salacious titles critical of Beijing, who later turned up on the mainland.

Four of the men are now under criminal investigation in China and the fifth is flitting between Hong Kong and the mainland, where he says he is "assisting" with the investigation.

That was preceded by other incidents, including attacks on journalists and accusations that Beijing is weighing in more heavily on the city's political and education systems.