The new underwater search for MH370 will focus on a 60,000 square kilometre area - compared to the 860km searched below the surface so far.
The new phase will have two elements - firstly the mapping of the sea floor, followed by a comprehensive search.
The mapping will take around three months to complete, Australian Deputy Prime Minister Warren Truss said, but will give "crucial" information for later search efforts, due to start in August.
More top news
Merrill Lynch has been fined £34.5 million for failing to report 68.5 million transactions, the Financial Conduct Authority has said.
Most people back a change in the law to ban unpaid internships that last for more than four weeks, a new poll suggests.
The favourites to win the Venice marathon finished behind a local runner - after they were led along the wrong route by a motorcycle guide.