The Immigration Department says people won't be able to get same-day tickets to register for new travel documents from July 13 onwards, and they'll have to book a slot, or make their applications online or by post.

Officials said they were scrapping the walk-in arrangement because of "queuing gangs".

Passport applications have surged following the pandemic, with 900,000 made in the first half of the year.

The department on Wednesday said that previously, around 30 percent of the time slots at its offices were left for people who just turned up, but now all 100 percent will go to those who book first.

Yeung Suk-yee, a principal immigration officer, said to help deal with the large number of applications in the system, eight offices will extend their opening hours on July 15 and 22.

She said extra staff have also been deployed as the summer holidays approach.

"We have contingency arrangements for the expired passports. To handle the [travel] peak, we have increased one-third of the manpower to handle the [surge] of applications," Yeung said.