Northern and central Tonga were slammed by Cyclone Rene on Monday, with powerful winds ripping off roofs, tearing down trees and power lines and cutting communications with the capital in the south of the country, officials said.

"We don't know the extent of the damage right now, though there are no reports of serious damage or injuries," the South Pacific nation's National Disaster Office deputy director, Mali'u Takai, said.

Contact with the northern Vavau island group was lost shortly after midnight as Cyclone Rene buffeted the low-lying atolls, tearing down trees, cutting roads and sparking coastal flooding as roiling seas surged ashore.

Initial reports were that the storm's winds had reached 115kph near the main northern town of Neiafu, then dropped to just 13kph as the cyclone's eye passed over the area. Damage was not as widespread as feared, he said.

The Ha'apai islands, middle grouping in the Tongan archipelago, "is also experiencing damage to trees, roads and power supplies," Takai said. "The seas there are rough and are going to get worse."

Tonga's Meteorological Office director Ofa Fa'anunu said they expected the storm centre to head toward the main island of Tongatapu later on Monday.

The cyclone was already sparking heavy rain and had cut power supplies in the capital, Nuku'alofa. Tonga has some 101,000 people.

Earlier, the office warned that the cyclone could "increase to very destructive hurricane force".

The storm missed both American Samoa, a US territory, and the neighbouring island nation of Samoa on Saturday, causing heavy rains, high winds and heavy sea swells but sparing more devastation to both areas, which were battered last year by a tsunami that killed 226 people.

Rene never made landfall on either American Samoa's main island of Tutuila or the Manu'a island group. At Sunday church services, residents of the US territory offered prayers and hymns of thanksgiving that American Samoa escaped the worst of the cyclone.

American Samoa Governor Togiola Tulafono said a preliminary report indicated minimal damage to homes and government property from the storm which did knock down trees and cause scattered power outages.

Tulafono confirmed there was one death indirectly caused by Rene - a 50-year-old man, who fell from a two-story apartment building while trying to board up a portion of the building on Friday.

He said the government was conducting a damage assessment on the main island and the Manu'a group.

About 300 people sought refuge at emergency shelters on Saturday morning, but many of them had returned to their homes by Sunday morning.

Tom Valahulu said via telephone from Fitiuta village in American Samoa's Manu'a island that he is very surprised more damage was not caused by the cyclone.

"The winds were very, very strong and my family kept running from one side of the house to the other side for safety when we heard the winds shifting around," Valahulu said. "The winds were really bad, and thankfully not much damage was caused and no deaths in my village."

Valahulu said he knew of three homes with "very bad damage" at Fitiuta village.

He said the strong winds uprooted banana trees and breadfruit trees, with a lot of debris.

A native of Tonga, Valahulu is very concerned for his family at Tonga's Vavau island. Valahulu said he is trying to reach his family via telephone.

Inter Island Airways, which provides domestic service, said there was no damage to the runways at the two domestic airports in Manu'a and fights resumed on Sunday morning. Flights were suspended last Thursday