Last year, an extradition bill that could have seen suspects from Hong Kong face trial in mainland China's murky courts sparked mass protests for months.
On Tuesday, Foreign Secretary Dominic Raab said the United Kingdom was in talks with countries in the Five Eyes alliance about how to handle a potential "exodus" of people from the area.
Johnson'scolumn in the paper was published as Hong Kong continues to clamp down on dissent and pro-democracy activities, including the prohibition, for the first time, of the annual June 4 vigil honouring victims of the Tiananmen Square massacre in 1989. And they live under the rule of law, administered by independent courts.
It has been approved by Beijing's parliament as necessary to tackling "terrorism" and "separatism".
But opponents, including many Western nations, fear it will bring mainland-style political oppression to a business hub that was supposedly guaranteed freedoms and autonomy for 50 years after its 1997 handover to China from Britain.
Around 350,000 people in Hong Kong now already have a BNO passport, but 2.6 million others are also eligible.
Among the changes he is proposing is the authorisation for Hong Kong residents carrying British National Overseas passports to have visa-free access to the United Kingdom for a renewable period of 12 months, instead of the current six-month limit.
Human-rights groups and parliamentarians, including Conservative MP Kenny Chiu, say they expect a further exodus from Hong Kong composed of three different streams of people: some of the 300,000 Hongkongers with Canadian citizenship, who comprise Canada's second-biggest overseas community; Hong Kong residents with relatives in Canada; and finally, people fleeing the crackdown who have no ties to Canada. No sitting PM has made a statement as bold as this on Hong Kong since the handover.
Pro-democracy activist Joshua Wong, holding a placard, speaks to media to urge European leaders against the national security law for Hong Kong outside the Legislative Council in Hong Kong on Wednesday.
He also said Hong Kongers born after 1997 would not be eligible to apply for the BNO passport, meaning this option may not be available to those under the age of 23.
American companies are nervous about a contentious national security law planned for Hong Kong and feel pessimistic about the city's medium term future, according to a new survey.
"It's lots of fear, there is no doubt about it".
He said any pathway opened up for Hong Kongers to travel to Australia would be welcome. "They value very much their own national security but are biased in viewing ours".
Critics say the law is a breach of Beijing's "one country, two systems" governing framework, which grants Macau and Hong Kong partial autonomy from China's Central Government.
Eddie Yue, chief executive of the HKMA, said on Tuesday the peg predates by nine years the 1992 U.S. Act which grants Hong Kong special status - whose provisions Washington is now reconsidering.
"There is an urgency to consider any measure that could be taken to help the Hong Kong people", she told SBS News.
"It can cross the Rubicon and violate the autonomy and the rights of the people of Hong Kong or it can step back, understand the widespread concern of the global community and live up to its responsibilities as a leading member of the worldwide community".