The launch of a travel bubble between Hong Kong and Singapore has been postponed for two weeks.
The decision comes amid a surge of Covid-19 cases in Hong Kong.
The air corridor, which would have allowed for quarantine-free travel between the two destinations, was due to kick in over the weekend.
Failure to launch is seen as a setback in efforts by the two financial hubs to revive their battered travel sectors.
Hong Kong reported 43 new infections on Saturday, the highest daily toll in nearly three months.
The number includes 13 cases with unknown transmission sources, raising fears the local outbreak could get out of control.
“This decision is a responsible decision,” Hong Kong commerce secretary, Edward Yau, said.
“For any scheme to be successful, it must fulfil the conditions of securing public health and also making sure that both sides are comfortable and feel safe about the scheme.”
The decision will be revisited in early December, Yau added.
Under the travel bubble arrangement, travellers would be required to take a Covid-19 test before departure and upon arrival.
There would be no restrictions on the purpose of travel, but passengers would have to take designated flights, and a maximum of 200 people would be allowed to travel each way per day.
A statemen from the Hong Kong Tourist Board added: “The Hong Kong Tourist Board supports air travel bubble taking visitors’ and the public’s safety as top priority.
“Under the new normal of the Covid-19 pandemic, it is inevitable that the pandemic situation fluctuates.
“It is a must for all of us to stay prudent in coping with the situation.
“The board hopes the pandemic situation in Hong Kong will soon stabilise and we look forward to welcoming visitors back when the time is right.”