Image copyright AFP Image caption Israel's PM Benjamin Netanyahu says his country helped stop "an unimaginable slaughter"

Israel helped avert an alleged terror plot in Australia to bring down a plane last year, both nations have confirmed.

Last July, Australian police charged two brothers over an alleged plan to blow up an Etihad Airways flight travelling from Sydney to Abu Dhabi.

In a speech in Jerusalem on Wednesday, Israeli PM Benjamin Netanyahu credited his nation's intelligence agencies with preventing "an unimaginable slaughter".

Authorities have said the alleged plot was linked to the Islamic State group.

At the time, Australian police said a home-made bomb, hidden inside a meat-grinder, was due to be carried on to a flight on 15 July but did not make it past security after the plan was aborted for an unknown reason.

Police said that when the bomb plot failed, the two suspects started on a second plot which involved creating an improvised chemical device designed to release hydrogen sulphide, or "rotten egg gas".

Lebanese-Australian brothers Khaled Khayat, 49, and Mahmoud Khayat, 32, were later arrested in Sydney and charged with "preparing for, or planning, a terrorist attack".

The AFP news agency said Israel did not reveal which flight was at the centre of its warning.

However, a tip-off from military intelligence group Unit 8200 - which is often likened to the US National Security Agency - had led to the arrests in Australia.

"The Israeli intelligence services thwarted the downing of an Australian plane, an unimaginable slaughter," Mr Netanyahu told Jewish-American leaders.

Image copyright Getty Images Image caption Australian police arrested two men last July amid a series of raids

"This would have caused a major disruption in global air transport and this is only one of dozens of terrorist attacks we have foiled around the world."

Australian Home Affairs Minister Peter Dutton said Israel was "directly" involved in uncovering the alleged plot.

"The Etihad flight was almost blown out of the sky and would have resulted in hundreds of people losing their lives so we are very grateful for the assistance Israel provided in that matter," Mr Dutton told local radio station 2GB.

Lebanon has said it also provided information to Australia over the case .

The alleged plot was among the most sophisticated ever attempted in Australia, police have said.

Police said the second alleged plan - involving the use of gas - was not close to fruition.