search operation for passengers of AirAsia flight QZ8501 in the Java Sea January 3, 2015.
An Indonesian search and rescue team member searching for passengers of AirAsia flight QZ8501 in the Java SeaReuters

Indonesian officials have revealed that search teams have discovered "four large objects" from the wreckage of AirAsia flight QZ8501.

The four large objects were reportedly found by an Indonesian navy ship's sonar.

Bambang Soelistyo, search and rescue agency chief, told the BBC that the larger of the newly discovered objects was 10x5m (32ft by 16dt).

He also revealed that the rescue team had found "oil slicks and huge objects" at late last night. Soelistyo said: "I am confident these are parts of the missing AirAsia plane."

A Russian amphibious plane has also recently arrived to help assist the search operation in Pangakalan Bun.

Search operators are hoping to locate the plane's black-box flight recorders and having been using specialist equipment in an attempt to unearth the important devices.

Rescue teams have also recovered a total of 30 bodies from the ocean – some believed to still be strapped to their seats onboard the doomed plane. No survivors have been found so far.

Six people have been identified, all of whom were Indonesian: Grayson Herbert Linaksita, Kevin Alexander Soetjipto, AirAsia stewardess Khairunnisa Haidar Fauzie, Hendra Gunawan Sawal, Ms Tejakusuma, and Hayati Lutfiah Hamid.

The recovered bodies have been transported in coffins and formally identified in Indonesia's second largest city, Surabaya.

It is believed the flight got into difficulty after trying to climb to 36,000ft to avoid a heavy storm.

Professor Edvin Aldrian, head of research at BMKG, commented: "From our data it looks like the last location of the plane had very bad weather and it was the biggest factor behind the crash."

Professor Aldrian also suggested there was evidence that the plane could have been affected by the extremely icy conditions at the plane's altitude. Aldrian said the conditions could have been bad enough to "stall the engines of the plane and freeze and damage the plane's machinery".

The Airbus A320 disappeared with 162 people on board while flying from Surabaya in Indonesia to Singapore.