Today will be the busiest search day so far for the missing Malaysian aircraft.

A warship with a black box detector is joining the mission in the Indian Ocean, to try and pick up a signal from the plane's transponder, before its batteries run out in a matter of days.

It's been confirmed several objects found floating yesterday in the search area are not from the plane.

Radar expert Mischa Dohler says time's running out to find the black box.

Meanwhile, Chinese relatives of the passengers on board the missing Malaysia Airlines flight have arrived in Kuala Lumpur.

They're demanding answers from the authorities who they accuse of holding back information.