The Tongan Navy Vessel VOEA Neiafu has been called on to conduct a rescue mission after authorities were alerted to a distress signal from a local fishing boat.
The Rescue Co-ordination Centre New Zealand picked up the live beacon activation and notified Tongan Police.
An Orion P-3 aircraft from New Zealand conducted an aerial search that located the boat at around 54 Nautical Miles south of Fua'amotu.
It confirmed there were 4 men on board and the boat engine had failed.
The VOEA Neiafu has left Nuku'alofa and is expected to reach the men later today.