Tonga's main island of Tongatapu has been spared the full force of Tropical Cyclone Tino.

The storm was expected to pass directly over Tongatapu overnight with the capital, Nuku'alofa on track to take a direct hit, instead the cyclone just passed to the North of Tongatapu without its high winds and heavy rain.

But the northern Tongan groups of Vava'u and Ha'apai were being hammered by destructive storm force winds and torrential downpours, with gusts estimated at 180km/hr yesterday.

Cyclone Tino has now weakened as it continues to move away from the islands of Tonga.

The cyclone has been downgraded to Category Two storm with winds up to 120 km/hr and momentary gusts up to 140 km/hr..

Emergency officials are meeting this morning, and have teams in the outer islands ready to start assessments

A short time ago the Cyclone Tino was around 435 kilometres East-Southeast of the Tongan capital of Nuku'alofa, heading southeast.

Paula Ma'u, director of Tonga's National Emergency Management Office (NEMO), told Matangi Tonga online yesterday evening that there were no casualties or injuries reported from throughout Tonga from the large cyclone.

"Our Met Office says the face of Tino was to the North where all the wind and rain was, but on the South side it turned a large blind eye on Tongatapu, even though it was so close."

"It is surprising to see the effects of nature," he said.

Severe Tropical Cyclone “TINO” Category 3 Forecast (Track map #11, Threat Track Map #9 and Wind Track Map #8)https://t.co/lK4juSVbXv pic.twitter.com/3FOzHMPAde — Tonga Portal (@tongaportal) January 18, 2020

Nuku'alofa and Tongatapu, home to most of the Tongan population, along with nearby 'Eua, are still recovering from extensive damage caused by Cyclone Gita only two years ago.

Dozens of evacuation centres were opened in Tonga in preparation for Tino and people were being urged to hunker down as Cyclone Tino moved closer to the Kingdom.

Paula Ma'u said the coastal areas of Tonga have been hit hard by storm surges from Cyclone Tino, which passed over Tonga at high tide.

Nomuka, located between Ha'apai and Tongatapu, was closest to the centre of the storm.

"We will start in Tongatapu to conduct a survey exercise covering the coastal areas, and agriculture and the villages. This will also be done by our teams in Ha'apai, Vava'u and the outer islands." he said.

International flights to Tonga were cancelled or delayed on Friday and Saturday Air New Zealand flights from Auckland and Air Fiji flights from Nadi were affected. All local domestic flights were cancelled.

Airlines are rescheduling passengers for Monday.

On Saturday, gale warnings had also been issued for Niue, and in Samoa, authorities there warned of the possibility of landslides and flooding. Strong winds fanned by Cyclone Tino had also brought down power to swathes of the main island Upolu, including the capital, Apia.