The 30-year old gloveman will now remain with the Sky Blues until at least the end of the 2012/13 season in what is a major coup for the club.
Necevski has wrestled back his first team spot from Liam Reddy, featuring in the last three matches where he has conceded just one goal, helping the reigning champs get their season back on track.
The Sydney-born shot-stopper admitted his delight at signing a new deal with the club and was looking forward to achieving more positive results in the near future.
"Sydney FC is a great club and I have stayed loyal to them since I arrived and they have repaid that," Necevski said. "I have remained positive the whole time I have been here. I have been patient, worked very hard and stayed strong mentally which is important.
"Sydney is my home town and I wanted to stay. I have a young family too so it feels good to know everything is settled and I can continue to push myself to be an even better keeper.
"I am obviously in the starting side now. I know I am good enough and I will be doing everything I possibly can to keep my spot.
"We have a very good team and of course we can make the top six. We have stayed positive from the get go and that will never change.
"We need to continue to build our momentum and we have a string of very important games coming up so we know what is required of us and we will work hard to get the results."