Modern Family's bumbling Phil Dunphy will have an allergic reaction to Vegemite and be attacked by a kangaroo in an upcoming Australian episode of the hit comedy.

Nolan Gould, who plays Phil's dim-witted son Luke in the series, has revealed that the family's holiday Down Under will prove challenging for the disaster-prone dad.

Phil Dunphy will not enjoy his trip down under for Modern Family.

"A whole bunch of things start happening to Phil," he told KIISFM on Wednesday.

"He's allergic to Vegemite and he gets hit by a kangaroo, and things like that."