An air force Hercules will leave for Tonga this afternoon with a navy dive team and a remote search team to help recover victims of the ferry disaster, Prime Minister John Key has announced.
He said assistance was being sent after consultations with the Tongan government.
"The three members of the remote search team will operate an underwater search vessel alongside the 12 members of the Operational Dive Team to carry out recovery of victims from the submerged ferry," Mr Key said in a statement.
"The latest deployment will join the air force Orion aircraft already in Tonga searching for survivors of the ferry sinking."
