The actress, who plays Anita Roy's long-lost mother Eva on the teen drama, confessed that she felt too old to strip off for the forthcoming 2011 release.
Speaking to Take 5 magazine, Murphy confessed: "They did ask, but I'll leave it to the younger girls!"
The 34-year-old remarked that her female co-stars have "such good little figures" and are "all toned".
She said: "I would never compare myself to them because I'm ten years older than some of them, I've had three kids and my body has changed. Still, I have upped the game a bit more since joining Hollyoaks."
Murphy recently predicted that Hollyoaks' ongoing revamp will help the show to better compete with rival soaps.