Smoke-filled Jetstar plane forced to land

Jetstar engineers are trying to find out what caused the cabin of one of its planes to fill with smoke en route from Sydney to Cairns.

The airline said the captain of the flight, which was forced to make an unscheduled landing in Brisbane, decided to shut down one of the engines as a precaution, and no emergency had been declared.

"While it's rare for something like this to happen, our crew are trained to deal with these type of situations and they handled the situation very professionally," Jetstar said.

Passengers took to social media to share their relief after the "terrifying" and "frightening" experience.

No one on the flight required medical attention.