NSW Premier Gladys Berejiklian has urged Victorians thinking of fleeing north to escape another COVID-19 lockdown to stay put.
Authorities are already worried the virus may have spread into the state, after several teams from a NSW sporting club visited one of the exposure sites.
Victoria will begin a seven-day lockdown from midnight in an effort to contain the outbreak that has grown to 26 cases and spread to 150 exposure sites.
NSW residents are being urged to avoid travel to Victoria, and anyone entering NSW from the southern state after 4pm on Thursday will still be required to abide by the lockdown rules.
Ms Berejiklian said NSW had no intention of closing the border to Victorians at this stage, despite every other state introducing travel restrictions for Melbourne or all of the state.
However, she urged Victorians not to take advantage of NSW's goodwill by rushing to cross the border before the 4pm deadline.
"There are 55 crossings of the border and we just ask everybody to do the right thing," she told Nine's Today Show on Thursday.
"Anybody who is intending to get in their car and try and beat the lockdown, please think about your fellow citizens.
"We've relied on the goodwill of our citizens during the entire pandemic. Let's not give up now."
The premier said once the Victorian lockdown - and its travel limitations - comes into effect at midnight, the pressure on NSW would ease.
Anyone who does enter NSW from Victoria after 4pm must remain at home for seven days, and is only permitted to leave for limited reasons.
However, NSW residents in border communities will only be required to abide by the rules if they go outside the border region from 4pm.
The update comes after members of the Tooleybuc Sporting Club in the NSW Riverina were instructed to self-isolate, with concerns the group were exposed to COVID-19 while attending an event at Cohuna in Victoria on Saturday.
"A few NSW teams were there, so we're ... making sure that everybody who has been exposed ... gets tested and isolates until further notice," Ms Berejiklian said.
The premier said the outbreak served as a reminder of the urgent need for NSW residents to roll up their sleeves and get vaccinated.
"What's happening in Victoria is a wake-up call. We don't know what's around the corner," she said.
NSW has now administered 1,175,707 jabs.
Australian Associated Press