Voters living in the federal seat of Eden-Monaro will head to the polls on July 4.
Speaker Tony Smith will issue the writ for the date on Thursday, with the close of nominations set for June 9.
Fiona Kotvojs is the Liberal candidate for the seat while former Bega mayor Kristy McBain is Labor's pick for the southern NSW electorate.
The seat was left vacant after Labor's Mike Kelly resigned last month due to poor health.
The poll date marks the start of the winter break for NSW schools.
Mr Smith says the usual advice from the Australian Electoral Commission is not to have elections during school holidays, but the coronavirus pandemic has changed that.
"The AEC has advised me that it is preferable to have a polling date where students and staff do not return to school on the very next Monday," he said.
"This will then enable a thorough sanitising clean after the completion of voting and counting at polling booths at New South Wales schools."
Dr Kotvojs narrowly lost to Mr Kelly a year ago in the federal election.
The former teacher, scientist and small business operator from Dignams Creek won preselection on Saturday night over defence department official Mark Schweikert.
Prime Minister Scott Morrison campaigned in Murrumbateman with Dr Kotvojs on Sunday, giving her a ringing endorsement.
Issues of climate change and bushfire recovery will be front and centre of the campaign, with areas of the electorate razed during the summer's devastating bushfires.
Labor's Ms McBain was Bega mayor during the bushfire crisis and hit the campaign trail earlier this month.
The Nationals and Greens are yet to announce candidates for the seat.
Australian Associated Press