A Royal New Zealand Air Force Orion was expected to lead the search for the Malaysia Airlines flight early today, as more ships headed to the massive area of sea off Western Australia.
By last night, the search effort had still not found the objects, which authorities hope could be wreckage from Flight MH370.
They were spotted by a satellite, and analysed and confirmed on Thursday.
The jet's disappearance has gripped the world for a fortnight but authorities warn that even if wreckage is found, it might be many months - or even longer - before the plane's black box could be recovered.
And there were fresh concerns yesterday that even that might not be possible, as the plane could be lost in a part of the Indian Ocean more than 5km deep. The area is about halfway between Australia and desolate islands off Antarctica, said to be one of the most remote and hostile locations on the planet.
Air Commodore Mike Yardley of the RNZAF was confident the plane would be found if it was in the area, despite stormy conditions complicating the search.
"The aircraft, the sensors and the people are excellent, so if there's something floating out there and in our area, we will find it - that I have no doubt about."
The size of the larger object spotted by satellites gave him hope the discovery could be the breakthrough families of the 239 passengers and crew were waiting for.
"It's certainly unusual in its size - 24 metres is very large," he said.
"All we can say is this is absolutely the best piece of information we've got, and we'll go out there until we can discount it."
The NZ Orion can fly as low as 70m above sea level, but because of the bad weather, it's so far got down to only 100m, just below the low cloud. It was expected to be one of the first planes to set off early today.
China is sending three warships to join the search, and a fourth Chinese vessel, an icebreaker, may also join them.
Authorities have not ruled out terrorism, or a hijacking, and have investigated the flight crew and explored the backgrounds of everyone on board.
Malaysia Airlines told the families yesterday that they could go to Australia if the debris were confirmed to be from Flight MH370.
"So far I don't think anyone is even thinking of taking the offer," a support worker said."You can say they are hoping against hope that their relatives are still alive and that the Australians are wrong."
The man who led the two-year search for an Air France jet that crashed into the Atlantic in 2009 said investigators faced a "colossal task" that was "far, far harder" than the French search.
Alain Bouillard, 63, said it took only six days for French and Brazilian naval forces to find the first bodies and the Airbus A330's tailpiece.
"This [Flight 370] disappearance is still a great mystery, and will lead to an inquiry and a search that is far, far harder than that we had looking for Air France 447," Mr Bouillard said.
"Firstly, we had many more clues. We knew that the Air France plane had a problem, thanks to 24 Acar [aircraft communications addressing and reporting system] messages sent over four minutes. We knew its precise location four minutes before impact, which allowed us to reduce our search zone to only 40 nautical miles," he said. "That is nothing compared to the surface area of today's search."
He said he would remain very "prudent" over sightings of debris, which could have drifted a considerable distance.
If these indeed prove to be from Flight MH370, Mr Bouillard said, experts would have to start studying the currents in this zone immediately to work out the "reverse drift" - a theoretical estimate of the initial position of bodies and debris by studying currents and winds in the crash area.
"Objects that have drifted for two weeks will have travelled a long way in that time," he said.
Adding to the challenge, the images of the debris were captured four days before they were analysed, meaning the debris itself could have floated much further east.
Mr Bouillard said: "After you have identified and examined some debris, you can piece together how the plane broke up. Was it in the air, was it during a sea landing, or did it hit the ocean surface? From that you can build up a scenario."
Prime Minister John Key, speaking from Hong Kong yesterday, did not rule out New Zealand sending more resources. "Ultimately it would be more air capability than sea capability. It's not unusual if you go back to other cases of this sort of thing, New Zealand has played a part in the past."
He said the nature of the help that would be needed was not yet known. However, New Zealand had sent specialist teams to international disasters before.
"The way the world has worked - we saw with the Christchurch earthquakes - is that each country develops specialist capability. Because of the nature of these kinds of disasters, you share that around."
- Staff reporters and agencies