After landing on runway 27 the crew of VH-TAD commenced taxying the aircraft along taxiway echo, back to the terminal. It was necessary to obtain a clearance to cross runway 34 on the way in. In the control tower the aerodrome controller issued a clearance to another aircraft to take off on runway 34. He also gave approval to the surface movement controller to allow VH-TAD to cross runway 34 behind the aircraft taking off. The surface movement controller then issued a clearance for VH-TAD to cross runway 34. In doing this he omitted to say to cross behind the departing aircraft. The crew of VH-TAD saw the other aircraft taking off on runway 34 and held VH-TAD short of runway 34 until the other aircraft had passed. Significant Factor The following factor was considered relevant to the development of the accident: 1. The surface movement controller incorrectly issued a clearance for VH-TAD to cross runway 34, in lieu of saying to cross behind the aircraft taking off on runway 34.