Two fresh signals have been picked up in the search for missing Malaysian flight MH370, Australian officials said on Wednesday, raising hopes that wreckage will be found within days even as the black box batteries start to expire.

Australian ship Ocean Shield detected the signals Tuesday to match a pair of transmissions picked up over the weekend that have been analyzed as consistent with signals from the plane's flight data recorder, the head of the search said on Wednesday.

Angus Houston, head of the Australian agency coordinating the search, struck an optimistic tone when announcing the information, but urged caution as the task of searching the remote Indian Ocean region remained enormous.

"I believe we are searching in the right area but we need to visually identify aircraft wreckage before we can confirm with certainty that this is the final resting place of MH370," Houston said.

The new transmissions lasted for five minutes and 32 seconds and about seven minutes respectively, Houston said.

Australia confirmed Wednesday that the first signals were consistent with black box recorders and that the search was narrowing.

"I'm now optimistic that we will find the aircraft, or what is left of the aircraft, in the not too distant future," Houston told the media.

However, experts were not that optimistic about whether the signals belong to MH370, as the process of teasing out those signals from the cacophony of background noise in the sea is a slow and exhausting process.

Read more in Special Coverage: