The Heart had a £2million ($3.1m) bid for the 32-year old forward rejected last week but Munn told Melbourne radio station SEN 1116 that the A-League outfit were still some sort of chance of luring the Canaries skipper to Australia.
"He's an interesting one. That's a bit more complicated," Munn said.
"He's the club captain there, and he's got two years to go but they've just spent eight-and-a-half million pounds on a Dutch striker (Ricky van Wolfswinkel). So clearly his position is under pressure.
"He played here as a 16, 17 year old in Perth, so we've talked to him, he's keen and he's certainly interested in Australia but the complexity is that he's still under contract and would need to be released."