The 31-year old winger joined the Heart from Hull City in August last year on a one-year deal and impressed enough in his debut campaign in Australia's top flight to clinch the clubs Players' Player of the Year award.
"We'd love to have him for another season," Munn told SEN 1116. "We were lucky enough to get Richie last year, late.
"He wasn't able to secure a deal (elsewhere) and we've put forward what we think is a really competitive offer.
"He's still having a look around what's in the marketplace and we're confident but until there's a piece of ink on a piece of paper...it's not a done deal."