The Government of New South Wales in Australia has decided to close its border with Victoria after a spike in new COVID-19 cases in the Melbourne area, affecting air traffic on one of the world's busiest routes between Sydney Kingsford Smith and Melbourne Tullamarine.

The closure will be enforced in stages, with residents of the Greater Melbourne area not allowed into New South Wales from 0001L on July 7, and all other residents of Victoria - from 0001L on July 8. While the government said that exceptions will be made for residents of the border regions and people undertaking essential travel, specific rules for these exceptions have yet to be released.

NSW premier Gladys Berejiklian said that for the initial 48-72 hours after the closure enters into force, inter-state travel could be totally suspended while the authorities determine what travel could be considered essential. She underlined that tourism would likely be excluded from the list of valid reasons for travel. The closure is a one-way decision by the government of NSW, meaning that entry into Victoria would not be restricted.

The Australian Capital Territory imposed a self-quarantine obligation on all travellers arriving from Victoria. ACT, which hosts the capital Canberra, does not share a border with Victoria and is surrounded by NSW on all sides.

Sydney-Melbourne route was the world's second-busiest in 2019, although current capacity has been severely restricted due to the pandemic. According to the ch-aviation capacities module, there are 22,400 scheduled one-way seats on the route during the week starting on July 6, 2020, which amounts to 85.3% of the entire NSW-Victoria market. Passenger services on the route are operated by Qantas (QF, Sydney Kingsford Smith) (8,916 weekly one-way seats), Jetstar Airways (JQ, Melbourne Tullamarine) (8,556), and Virgin Australia International (VA, Brisbane Int'l) (4,928).

Both Qantas (the parent of Jetstar) and Virgin said they were reviewing their schedule between the cities.

Besides the three big airlines, limited passenger services between NSW and Victoria are also operated by Rex - Regional Express (ZL, Wagga Wagga) (from Albury and Merimbula to Tullamarine), Fly Corporate (FC, Canberra) (from Orange, NS and Wollongong to Melbourne Essendon), and Sharp Airlines (SH, Hamilton, VI) (from Griffith to Essendon).