The Hollyoaks and Emmerdale actress, who has 9-year-old Taylor, 6-year-old Ruby and 2-year-old Matilda with her footballer husband Harry Kewell, said that they have planned to have four children altogether.
Murphy told New Idea magazine: "We'd like four. I'd love another baby. I think it's just a case of if we're lucky enough to fall pregnant again and if we can fit it in. But that's the plan."
Talking about her long-distance marriage with Turkey-based Kewell, she added: "Obviously Harry is fulfilling his dreams, but he's providing a nice life for us too. When he first went over there we looked at houses and schools but the nearest international school was an hour's drive away.
"With football, you never know how long you're going to be there, so we decided to play it by ear. We made a pact when he left - if it ever became too hard for us, we'd stop."