The new deal will keep the 26-year-old at Blackburn until the summer of 2013.
“I’m absolutely delighted to get another two-and-a-half years at the club,” Bunn told the club’s official website.
“It couldn’t have gone any better. I’ve played a few games recently, which I thought I did well in, and I want to take it further. To get a new deal is great news.”
