Wollondilly councillor Matt Smith has resigned due to personal health reasons, effective immediately.
The Appin resident handed his notice of resignation to the council on Tuesday, June 23 - just over a year before the state's council elections are due to take place.
Wollondilly mayor Matthew Deeth thanked Mr Smith for his service to the Wollondilly community and wished him the very best in his future endeavours.
Mr Smith became a councillor after winning the East Ward by-election in October, 27 2017 following the resignation of former councillor Ray Law.
Some highlights during Mr Smith's time on the council included the successful advocacy for the construction of a new skate park in Appin, which was officially opened yesterday, and vital upgrades to Wollondilly roads.
The council will consider a proposal to seek ministerial approval that the vacancy not be filled until next year's general election.
This will be considered at an extraordinary meeting of the council next Tuesday.
The resignation came as the council was seeking legal advice as to whether Mr Smith officially attended last Tuesday's online ordinary meeting as per the Local Government Act, as he attended the meeting by voice only after experiencing technical difficulties appearing on video.
If Mr Smith did not officially attend it would make it the third consecutive council meeting not attended.
Under the Local Government Act, the council's chief executive Ben Taylor is required to consider whether a councillor's position has become vacant in these circumstances, also taking into consideration legislated changes in the current COVID 19 environment.
The resignation was submitted before the legal advice was received for Mr Taylor to make a determination.