Professor Lau Siu-kai, vice-chairman of the Chinese Association of Hong Kong and Macau Studies, a semi-official think tank, said Xi delivered a tougher message than in speeches by former presidents Hu Jintao and Jiang Zemin.

“He candidly stated Beijing’s dissatisfaction towards Hong Kong after the handover, as well as saying the city’s needs to improve systems to uphold national sovereignty,” Lau said.

“Maybe it is not necessary for Lam to enact the law at once, but she has to pave the way by creating the atmosphere to do so,” Lau said.

A previous attempt to legislate for Article 23 in 2003 was shelved after 500,000 people took to the streets, and a plan for national education was dropped in 2012 after protests by students, parents and teachers.

In the latter part of his speech, Xi adopted a softer stance by calling on the public to solve problems through sensible communication instead of political confrontation.

“On the part of the central government, we are ready to talk to anyone who loves the country, loves Hong Kong and genuinely supports the principle of ‘one country, two systems’ and the Basic Law of the HKSAR, no matter what political views or position he or she may hold,” he said.

While Lau emphasised such talks were based on the precondition of respecting national sovereignty, Civic Party leader Alvin Yeung Ngok-kiu said he would not readily take Xi’s remarks as an olive branch.

“Such a message coming from Xi of course has its significance and weight, but actions speak for everything,” Yeung said. “I do not think we should entertain too many unnecessary fantasies right now.”

Yeung hoped Lam could ditch the combative style of her predecessor, Leung Chun-ying, and improve the government’s relations with pan-democrats. That, he said, would help lay the foundation for better relations between Beijing and his camp.

Democratic Party chairman Wu Chi-wai expressed disappointment with Xi’s speech, saying the president had focused on the importance of one country and the city’s economic development, but failed to elaborate on how to respect the two systems.

It was normal and irrefutable for Beijing to put the emphasis on national sovereignty, Wu said, but he worried such a strong stance would end up being a means for the central government to dwarf the two systems.

“Merely focusing on economic development will eventually turn Hong Kong into just another Chinese city that lacks the characteristics of two systems,” Wu said. “It is the freedoms Hong Kong enjoys that make it a civilised city.”

Former Civic Party lawmaker Ronny Tong Ka-wah, a newly appointed member of Lam’s Executive Council, said Xi gave a single message throughout his speech – the importance of respecting national sovereignty.

Tong believed the president was targeting the warning only at pro-independence forces and had sent a positive signal for future communications between pan-democrats and Beijing, as long as the pan-democrats did not step on the “red line”.

“It is a good thing to draw clearly the lines and avoid unnecessary misunderstandings,” Tong said.

Eduction sector lawmaker Ip Kin-yuen was concerned by Xi’s call to step up patriotic education, worrying it would only convey the positive sides of China to pupils.

The purpose of civic education was to develop independent thinking, he said.