The crew noticed the problem at an altitude of about 7,000 feet, and sought clearance from air traffic control at Perth airport before landing at 3.15 p.m. local time, The Australian reported.
"Soon after take-off, the flight crew detected some vibration in the left-hand engine of the Boeing 767 aircraft. This wasn't an engine failure and the pilot didn't have to turn the engine off. The engine was just put into idle to lower the thrust to a manageable level," a spokesman said.
All passengers were put on other flights out of Perth and they have reached Melbourne, the spokesman said.
The spokesman added that the problem with the Boeing 767 had nothing to do with concerns over Qantas' Airbus A380 fleet.
The airline has grounded all six of its A380s after a flight from Singapore to Sydney turned back when one of its four engines exploded over Indonesia Nov 4.
The next day, Nov 5, a Boeing 747 with 412 passengers and 19 crew on board returned to Singapore's Changi airport after an engine failure.