There's a new lava lobe on Tonga's Home Reef Volcano, covering close to half the island, and which has grown nearly twice the size that it was when the thermal anomaly was first detected.
Thermal anomalies have continued to be detected on Home Reef Volcano, located south west of Vava'u and north west of Ha'apai, since 4 December.
However, Tonga's Geological Services said there are no indicators for major explosive eruptions.
The volcanic activity poses a low risk to the Vava'u and Ha'apai communities.
Tonga's Geological Services senior geologist, Mele Manu said there is a new lava flow lobe on the northern shoreline of the volcano.
"The overall area of the island is approximately 158,000 square metres and 42 percent of this area is covered by the new lava lobe," Manu said.
She said when the thermal anomaly was first detected the island was 85,000 square metres.
Manu said a stream of pumice from Tonga's Home Reef Volcano might be created if it becomes more active.
"Just in case there will be an increase in volcanic activities a pumice raft might be created - then most likely some of the pumice will drift to the southern islands of Vava'u.
"It is less likely that this will happen to Ha'apai - that's just because of the direction of the sea current."
All mariners are advised to remain at least two nautical miles away from Home Reef.
Correction: This story previously stated Home Reef Volcano was 85 square metres in size when the thermal anomaly was first detected. It was actually 85,000 square metres.