About 45,000 people had crossed between Hong Kong and the mainland by 8pm on Sunday, Immigration Department figures showed, as people made the most of the first day of quarantine-free travel.

The figure, which includes four land crossing points but not air travel, fell well short of the 50,000 spaces available for journeys in each direction. About 33,000 of the travellers were heading from Hong Kong to the mainland.

Almost 44,000 people passed through Hong Kong International Airport, the official figures show, although that includes people heading to and from destinations overseas.

The Secretary for Security, Chris Tang, said earlier that about half of Sunday's quota had been booked up.

People travelling across the border said the process had generally been smooth. One businessman told international media that the crossing had been almost as smooth as before the pandemic.

"I have only seen my sister twice in three years," a Mrs Lau told RTHK. "I'm so excited and delighted. Before the pandemic, I usually went back to the mainland every week."

Speaking after a visit to the Lok Ma Chau checkpoint, where most land travellers are crossing, Chief Executive John Lee said he hoped to eventually resume travel without a quota.

He said spaces were still available for travel around the Lunar New Year holiday, although only a handful of slots were free on Lunar New Year's Eve, January 20.