Grieving relatives of passengers on board Flight MH370 today launched a USD 5 million reward for a whistleblower who can provide key information and aid their search to trace the jet that went missing mysteriously three months ago on this day.

After three months of failed search efforts, families have become convinced the authorities are concealing the truth about the disappearance of the Boeing 777-200 and launched the crowd-funding campaign in a bid to get answers.

The 'Reward MH370' campaign aims to raise at least USD 5 million "to encourage a whistleblower to come forward with information".

The USD 3 million would go to a whistleblower who would forward with key information related to the incident. Another USD 2 million will be utilised for hiring private investigators to follow up on leads.

The Malaysia Airlines jet disappeared from radar screens on March 8 en route from Kuala Lumpur to Beijing with 239 people, including five Indians, aboard.

The Boeing 777 is believed to have crashed in the southern Indian Ocean, but an extensive search has turned up no sign of wreckage so far.

"We are convinced that somewhere, someone knows something, and we hope this reward will entice him or her to come forward," said Ethan Hunt, who is heading the campaign.

"We are taking matters into our own hands," SAID Sarah Bajc, whose partner Philip Wood, 50, was on the flight.

"The relatives hope they turn up a whistle-blower who says, 'I know where to find this,' or a flight controller who can access new data, but expect they will also encounter some unethical people."

The campaign, which was launched on Indiegogo, comes as Malaysia's acting Transport Minister Hishammuddin Hussein condemned Boeing and Rolls Royce this week for their part in the search for the missing jet and has hit back that responsibility for the entire investigation should fall on Malaysia, Australia and China.

Meanwhile, Australian transportation authorities are now moving to a revised underwater search zone in the southern Indian Ocean.

The search will enter a new phase covering a 60,000-square-kilometre area along MH370’s probable flight arc over the southern Indian Ocean, but only after a bathymetric survey map of the sea floor is completed within a three-month window.

"The latest information and analysis confirms that MH370 will be found in close proximity to the arc," the Australian Transport Safety Bureau said in a statement.

"At the time MH370 reached this arc, the aircraft is considered to have exhausted its fuel and to have been descending."