Blanch, 29, has scored 33 tries in 47 Super League appearances for the Dragons since arriving from Wakefield, and will now stay in Perpignan until the end of 2014.
He said: “I’m of course disappointed with Trent Robinson leaving at the end of the season. The last two seasons were really good for me, I’ve probably played my best rugby for the last two years.
“But I’m more than happy to extend my contract for the next two years. My family loves the life here and I love the football life, on and off the field.
“Early in my career, I would never have thought that I would have been in a position to be in a club who can win a Final. And even without Trent next year, we will still have a chance to chase for a title with the quality players we’ve got here.”
The Australian famously paid his own air fare to sign a deal with Castleford in 2006, scoring four tries in six appearances.
He then moved on to then National League 1 club Widnes, where he scored 28 tries in 39 appearances, to catch the attention of Wakefield.
After another prolific spell there, where he scored 36 tries in 52 appearances, he headed to France at the start of the 2011 season.