Chief Executive, John Lee, said on Sunday that Hong Kong will strive to achieve a full resumption of travel with the mainland as soon as possible.

He was speaking after visiting the Lok Mau Chau border check point shortly after it reopened to quarantine-free travel for the first time in three years.

Lee said customs clearance on the first day of the resumption of travel across the frontier had been smooth, adding that he believed the 50,000 daily quota for the border crossings was adequate.

Besides the places now available each way at land crossings, about 10,000 spaces for flights, ferry trips or bus crossings of the bridge to Zhuhai are also available daily.

The CE said all the relevant border control points were in good operation but that Hong Kong is seeking to further expand the total number of crossing points from the current seven to the full 14.

"The goal is to get back to normalcy as soon as possible," Lee said.

"The time will come when we no longer use the quota system but as to when, we have to closely monitor the situation."

Up to 35,000 people can now head north each day via bookings through the Lok Ma Chau crossing, with the same number of mainlanders able to travel in the opposite direction.

Another 15,000 can register online to cross the border at Shenzhen Bay and Man Kam To, which also reopened on Sunday.

The Xinhua news agency said Shenzhen and Hong Kong will review the first phase of border reopening in one week's time. It said on the basis of the consensus reached by both sides, the arrangement of the second phase will be announced.

The MTR Corporation said that as of 5pm Sunday, a total of 16,500 passengers had passed through Lok Ma Chau.

It said trains to the border control point were running at four to eight-minute intervals.