CANBERRA, March 22 (Xinhua) -- The chances of finding the traces of missing Malaysia Airlines flight MH370 in the Indian Ocean southwest of Australia are diminishing by the day, an Australian expert said Saturday.

As the search entered its third week, bad weather was closing in on the search band threatening to erase any possibility of finding the object spotted in a satellite photograph from March 16, said Dr John Blaxland, senior fellow at the Strategic and Defence Studies Centre of the Australian National University in Canberra.

"We have to be realistic about this if not a little pessimistic. The chances of this being found and being identified as being part of an aircraft are getting very slim," Blaxland told Xinhua in his office.

The object was possibly just a shipping container that had fallen overboard at some stage and was submerged just below the surface of the water.

It could also have drifted a vast distance from the area where the photo was taken and may even have sunk already, said Blaxland.

"This is something that is just below the water line. There are no emanations that we know of and there's no indication of this having any sort of beacon or identifier that is detectable from any electronic means, let alone visually," he said.

A visual sighting would be the most reliable and likely method of finding the object because it was so very hard to detect, he said.

"This is just below the surface. We don't know what it is. We don't know what material it's made of. We suspect it's made of metal, but we're not sure."

Finding pieces of the aircraft soon would be essential to tracing the black box flight data and cockpit voice recorders, which could be the only way to solve the mystery of the aircraft's disappearance.

"The black box has a signal and that has only got a few days left to go before the battery runs out and then we will be in a very different circumstance, then we will be in a situation where we could potentially be searching for years," said Blaxland.

"We're all hoping to find that needle in a haystack."

Saturday was probably the best chance of finding anything with the weather closing in, but even in good conditions, objects below the surface could be hidden by the movement of the waves and light reflections.

"We all hope and pray that we find something but we have to be realistic about the prospects of success in the short term and they're not great, they're not great. This is a remote prospect," he said.

"People are putting in a concerted effort and I think it's fair to say the Australian government is trying as hard as it can to collaborate, to focus in on this task."