A planned travel bubble between Hong Kong and Singapore was scrapped a day before its launch on Saturday after the southern Chinese city announced a sudden spike in coronavirus cases.

The decision is both a blow to the two cities' battered tourist industries and also for other countries who had been hoping the scheme might be a model to replicate during the pandemic.

The two financial hubs have both suffered mild outbreaks. But with small populations and a heavy dependence on links to the outside world they have been hard hit as the global economy collapsed.

Desperate to help their key tourism and aviation sectors, they came up with the plan allowing limited, quarantine-free travel between the cities as long as visitors test negative for Covid-19.

The travel corridor was set to kick off on Sunday morning.

Hong Kong's tourist industry has been hard hit by the coronavirus pandemic, with travel restrictions severely limiting arrivals
Hong Kong's tourist industry has been hard hit by the coronavirus pandemic, with travel restrictions severely limiting arrivals AFP / Dale DE LA REY

But on Saturday, Hong Kong announced the scheme would have to be delayed for two weeks following a sudden rise in coronavirus infections.

"In the light of recent surge of local cases we have decided, together with the Singapore government, to defer the air travel bubble's launch by two weeks," commerce secretary Edward Yau told reporters.

After weeks of single-digit infections, Hong Kong health authorities reported 36 local coronavirus on Saturday.

Crucially, 13 were from unknown transmission sources, prompting fears the city has a new wave of out-of-control infections.

The sudden spike was enough for authorities in both cities to postpone the travel bubble.

"This is a sober reminder that the Covid-19 virus is still with us, and even as we fight to regain our normal lives, the journey will be full of ups and downs," Singapore transport minister Ong Ye Kung wrote on his Facebook page.

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