Dominic Perrottet will receive the first feedback on his premiership when residents in the seats of Bega, Willoughby, Monaro and Strathfield vote on February 12.
While technological problems mean residents will not be able to minimise the risk of contracting the virus by voting online, the NSW Electoral Commission on Friday announced voters will have the option to cast their ballot via post.
The state's iVote system - designed to mitigate COVID-19 risks - crashed during the local government elections held on December 4.
With no time to fix the glitches before the by-elections, postal voting packs will instead be sent to every voter enrolled in the four districts, NSW Electoral Commissioner John Schmidt said.
Usually those wishing to vote remotely have to apply for a pack themselves.
"To help reduce the risk of COVID-19 transmission ... voters can choose to vote via post, or in person at our voting centres," he said.
"People using postal voting are encouraged to make sure they follow the instructions in the pack to complete their postal vote before 6pm, Saturday, 12 February, and get their ballot papers back to us by the cut-off for accepting postal votes on Friday, 25 February."
Those who want to vote in person can start from January 31.
All voting centres will adhere to COVID-safe election guidelines, including mandatory mask-wearing, physical distancing, single-use pens, queue management and QR-code check ins.
The by-elections are the result of a series of resignations of senior figures across both sides of the aisle.
For the last 18 years, Willoughby has been held by former premier Gladys Berejiklian, who stepped down from the state's top job in October after her conduct was referred to the Independent Commission Against Corruption.
Monaro was vacated by former deputy premier John Barilaro, Bega by former transport minister Andrew Constance, and Strathfield by former opposition leader Jodi McKay.
Mr Barilaro and Ms McKay have retired from politics, while Mr Constance has been selected as the Liberal candidate to run for the federal seat of Gilmore in the upcoming federal election.
Former United Nations lawyer turned investment firm chairman Jason Yat-sen Li will contest Strathfield for Labor, going up against Liberal candidate Bridget Sakr - whose 11-year-old daughter died along with three other children when they were hit by a drunk and drugged driver at Oatlands in 2020.
The Liberal candidate for Willoughby, a safe lower north shore seat, is Tim James, who is executive director of the Menzies Research Centre think tank and former chief-of-staff to Planning Minister Anthony Roberts.
In Bega, farmer and former teacher Fiona Kotvojs will aim to continue the Liberal party's 33-year hold over the seat, running against Labor's Michael Holland, a south coast gynaecologist and obstetrician.
Nichole Overall and Bryce Wilson will face off in the Monaro by-election for the Nationals and Labor respectively.
Meanwhile, five local government by-elections are slated to take place on February 26.