Police and the army will prevent people entering NSW from Victoria without a permit with drones to monitor crossing points.
Premier Gladys Berejiklian said border communities would be particularly impacted by the closures in coming days, while NSW Police Commissioner Mick Fuller said crossing the river would be difficult, but not impossible.
The closure is set to start at 11.59pm on Tuesday and will be enforced on the NSW side.
Those looking to enter NSW from Victoria would be able to apply for exemptions from Service NSW.
He said police would take a "sensible but pragmatic approach" when assessing those who could cross.
Speaking at a press conference on Monday, Commissioner Fuller said a wide range of resources would be used to monitor the closures.
"We want people to take this seriously," he said.
"Do not underestimate the pain all Victorians are going through, we don't want that in NSW."
Each crossing point will be manned.
Police have been in meetings on Monday to work through the closures.
The North East has a large number of crossings, including the Hume Highway, Lincoln Causeway, Bethanga Bridge, two bridges between Corowa and Wahgunyah, and two Yarrawonga-Mulwala crossings.
Those returning to NSW from Victoria will have to isolate for 14 days.