Foreign Secretary Dominic Raab will set out later what action the UK will take in response to China’s imposition of an “anti-protest” law in Hong Kong.
He has warned Beijing that eroding Hong Kong’s autonomy risks “violating” legal obligations entered into when it took control of the ex-UK colony in 1997.
The UK says it is ready to help Hong Kong citizens with British overseas passports to come to the country.
China rejects criticism of its actions, on what it says are internal matters.
Hong Kong’s new national security law, which targets secession, subversion and terrorism with punishments up to life in prison, came into effect on Tuesday.
Critics say it effectively puts an end to the “one country, two systems” principle enshrined in the 1985 Joint Declaration, a legally binding agreement signed by the UK and China which protected certain freedoms in the territory for at least 50 years.
The UK government is under pressure to take a firm line with Beijing from MPs on all sides of the Commons, who are worried about China’s increasingly assertive role regionally and the security implications of Chinese firm Huawei’s involvement in the UK’s 5G network.
Speaking on Tuesday, Mr Raab said he would set out the UK’s next steps after government lawyers had studied the details of the national security legislation.
But Mr Raab, who will make a statement at about 12.40 BST, said China’s actions were “deeply troubling” and the UK would work with its G7 partners to put pressure on Beijing to think again.
He also re-stated the UK’s commitment to make it easier for the 350,000 or so Hong Kong residents who are British National Overseas Passport holders to come to the UK, as well as the 2.6 million others are also eligible.
At the moment, they are entitled to visa-free access to the UK for six months but Prime Minister Boris Johnson has said that, if the national security law passes, this will be extended to 12 months with the right to renew.
As a mark of the UK’s “profound ties of history” with Hong Kong, Mr Johnson has said the UK will go further and give those who are eligible further immigration rights, including the right to work, as part of a potential route to British citizenship.
In an article earlier this month, Mr Johnson said this would represent one of the biggest shake-ups of UK visa rule in recent history.
Labour said the government must “not waver” from its obligations to the people of Hong Kong and it expected the foreign secretary to lay out “concrete steps” to uphold the freedoms of those living there.
“The government promised action,” said shadow foreign secretary Lisa Nandy. “Now is not the moment to look away.”
On Wednesday, several people were arrested in Hong Kong, including a man carrying a pro-independence flag as police used pepper spray to disperse some protesters gathered to mark 23 years since British rule ended.
The annual pro-democracy march to mark the anniversary had been banned for the first time by authorities, who cited a bar on gatherings of more than 50 people because of Covid-19.