The actor is though to be planning a permanent move to the US as he prepares to welcome his first child with fiancée and former co-star Jessica Marais, reports the Australian Daily Telegraph.
Stewart has played Jake Barton on the show since its second series, becoming a cast regular in series three.
"The production is about to wind up for two to three months," a Seven Network spokesperson told the paper. "We don't know whether he'll be back at this stage. That's still being worked out. This show is like any family. The kids will come and go.
"When young people are at a certain stage of their careers, you have to be flexible. Rafters is performing superbly - especially when you consider it's up against a phenomenon [in The Voice Australia]. It's like Ayers Rock. It's strong and it's got heart."
Hugh Sheridan recently reassured viewers that although he has signed a talent agreement with Channel Ten, the door has been left open for his Packed to the Rafters character Ben Rafter.
Seven bosses were forced to deny reports last month suggesting that series stars Rebecca Gibney and Erik Thomson had asked to leave the show.