Dozens of people on a flight bound for Hobart have had a Covid-19 scare after two passengers learned they were close contacts of a positive case after already boarding the plane.

It’s understood the two passengers immediately let flight crew know before being directed off the Jetstar flight for urgent Covid-19 testing about 2.30pm on Wednesday.

Their tests came back as negative, clearing all the other passengers of any possible infection.

Passengers were given the option of travelling or not, with the flight scheduled for takeoff about 3pm instead departing Sydney airport about 5pm.

A number of states introduced hard border measures with NSW on Wednesday due to an escalating outbreak of coronavirus in Bondi.

South Australia and Western Australia reintroduced a hard border on Wednesday, while three other jurisdictions cut off large parts of Sydney.

Travellers from NSW were no longer permitted to enter WA or SA “effective immediately”.

Meanwhile Queensland, Victoria and Tasmania barred entry from a number of Sydney local government areas, and the ACT implemented a “stay-at-home” requirement.

New Zealand halted its quarantine-free travel bubble with NSW on Tuesday.

The pause took effect from 11.59pm on Tuesday and was scheduled to last for 72 hours, the country’s government officials announced on Tuesday.

Case numbers almost doubled for the second day in a row on Wednesday after 16 new locally acquired cases lifted the Bondi cluster to 37.