It builds on the sweeping legislation that Beijing imposed on the city in 2020 following massive pro-democracy protests the year before.

Hong Kong has been required to pass a law that prohibits 'acts that endanger national security' - known as Article 23 - since it was handed over to China in 1997.

However, earlier attempts were put on hold.

In 2003 an estimated half a million people protested and the security minister then was forced to resign.

"Why now? We can't wait."

Officials - including the city's leader Chief Executive John Lee who is sanctioned by the U.S. - on Tuesday explained why they want to enact Article 23 "as soon as possible":

"We still have to watch out for potential sabotage, undercurrents that try to create troubles, particularly some of the independent Hong Kong ideas are still being embedded in some people's minds, and some foreign agents may still be active in Hong Kong."

Some legal scholars say the new legislation could sharpen the 2020 law, which is at times vaguely worded, and rework older laws dating back to the colonial era.

New laws have been drafted including one that deals with sedition - and specifically mentions violent protests that endanger national sovereignty.

There's also a new law against computer-based actions that harm national security.

Lee also said the legislation would not call for transfer of people over the border to mainland China.

"The law we are legislating will have no element at all about sending any arrested persons in Hong Kong to the mainland."

Lee said that the security legislation will respect peoples' and organizations' rights and freedoms and meet international standards.

He has made it a policy goal to bring the shelved Article 23 back by this year.

"When people see that this law will bring security and also stability they will love it."

Lee's policy focus, he announced last year, was stimulating the city's economy - when the local stock market had struggled and as some families have sold flats and moved abroad.

Public consultation on the legislation is set to end February 28.