Hong Kong’s leader said Monday that anyone who objects to the installation of a Chinese checkpoint at a local railway station is fundamentally ill-informed.

Protests erupted in the former British colony on New Year’s Day after Beijing lawmakers voted to allow Chinese immigration checks and the enforcement of Chinese laws in a part of Hong Kong’s West Kowloon station. It’s specifically for passengers taking a high-speed train to Guangzhou and Shenzhen, which is due to launch in September. Known as “co-location,” the arrangement will effectively see a quarter of the West Kowloon terminal leased out to Beijing.

Public opposition to the move “reflects a sort of lack of full understanding of the constitutional regime,” Hong Kong Chief Executive Carrie Lam told CNBC on Monday from the sidelines of the Asian Financial Forum.

The move is aimed at increasing efficiency so individuals departing from Hong Kong won’t have to go undergo clearance procedures in China — “otherwise you have to get off the train across the border and then find another train, it just doesn’t make sense,” said Lam, who added there’s “a solid legal basis” to support co-location. A similar arrangement exists at the Shenzhen Bay Port, which sits on the Hong Kong-China border.

But many locals, including the city’s bar association chief, have said the West Kowloon co-location deal undermines Hong Kong’s independent legal system.

Considered a special administrative region of China, the financial hub is meant to enjoy a high degree of autonomy under a principle known as “One Country, Two Systems.” However, a spate of episodes in recent years suggests increasing Chinese interference in domestic affairs, such as Beijing’s historic 2016 ruling on a court case involving pro-independence politicians.

More than three years since the city’s democracy protests, the movement is still in full force — activists recently organised a primary vote ahead of upcoming by-elections for seats in the city’s legislature.

Addressing the issue, Lam said she has done everything possible to “engage Legislative Council members and politicians from across the political spectrum.”