The new deal will see McIlwrick remain with Wests Tigers until at least the end of the 2019 season.
Since arriving at Wests Tigers earlier this year, McIlwrick has played every game for the club so far this season — cementing himself as the starting hooker on every occasion.
The crafty hooker has played 14 games for Wests Tigers in 2017, taking his career total to 43 games since making his first-grade debut for the Canberra Raiders in 2012.
The 26-year-old said he was delighted to be able to remain with Wests Tigers for the next two seasons.
