An increase in the number of incidents involving lithium batteries has prompted the Civil Aviation Safety Authority to warn passengers not to put the power packs in their checked luggage because of the danger of fire.

CASA says the batteries -- used extensively in laptops, mobile phones and music players -- have the potential to short-circuit and burn under certain conditions and the preference is to have spare batteries carried in the cabin with their terminals appropriately insulated.

"Cabin crew and flight crew are specifically trained in the management and handling of dangerous goods incidents in the aircraft cabin, including those caused by lithium battery fires, and can respond quickly if an incident arises," CASA aviation safety director John McCormick said.

The warning echoes those issued by other regulators after the batteries were implicated in the crash of a UPS freighter in Dubai last September and suspicions about an Asiana Airlines Boeing 747 crash last week. The U.S. Federal Aviation Administration logged 113 incidents involving batteries and smoke, fire or extreme heat between 1991 and last year.

CASA has also received reports of singed batteries in Australia, although airlines say there has not been a major incident.

Virgin Australia and Qantas require passengers to carry spare batteries in their cabin baggage and ban those above certain capacities from aircraft completely.

Qantas has been forced on occasion to retrieve checked baggage because people had put spare batteries in their suitcases without realising it was against the rules and a spokesman said it was looking at providing passengers with additional information.

Meanwhile, Virgin Australia is under investigation by the Australian Transport Safety Bureau after an Embraer 190 travelling from Sydney flew 700ft lower than its assigned altitude as it approached Melbourne in turbulence.

The airline is also conducting an internal investigation but noted there was no suggestion the aircraft had operated below the minimum safe altitude.