The closure will be effective from 12.01am Wednesday, 8 July and follows the concerning spread of COVID-19 in Melbourne.
Premier Gladys Berejiklian said the decision was made after consulting with the NSW Chief Health Officer and discussions with the Prime Minister and Victorian Premier Dan Andrews.
“The people of NSW have done an incredible job to help stop the spread of COVID-19, allowing us to open up our economy,” Ms Berejiklian said.
“The outbreak of cases we are seeing in Victoria is putting these gains at risk.
“I do not take this step lightly, but have always said we will do what we must to protect the health and jobs of NSW residents.”
Ms Berejiklian stressed the border closure is a temporary measure.
“As I have said before, it is in our national interest for borders to be open,” Ms Berejiklian said.
Health Minister Brad Hazzard said the swift action is necessary to protect NSW residents and to assist Victoria in their attempts to bring the outbreak under control.
“We must remain flexible throughout this ongoing pandemic and adjust our strategies as the threat grows and recedes,” Mr Hazzard said.
“This is not the first spike and it is unlikely to be the last.”
NSW residents returning from a Melbourne hotspot are already required to go into 14 days of self-isolation. This requirement will be extended to anyone returning from Victoria. This will be backed by heavy penalties and fines.
There will be provisions in place for residents of border regions, such as Albury-Wodonga.
Special conditions will be in place for freight operations and other critical services.
NSW Police Commissioner Mick Fuller said a hard border would be established at appropriate locations to enforce the border closure.
“The NSW Police Force is ready to step up, 400 police officers plus other agencies are preparing to enforce the closure of the NSW and Victorian border,” Commissioner Fuller said.
NSW Chief Health Officer Dr Kerry Chant said the measure will ensure NSW citizens are protected, and she urged residents here to remain vigilant and continue to present for testing.
“The Victorian increase in community transmission has been particularly worrying,” Dr Chant said.
“This is a warning for NSW that the pandemic is not over.”