WELLINGTON, New Zealand (AP) -- A new volcanic island has risen from the South Pacific near Tonga, according to reports from two vessels that passed the area.

The crew of the Maiken, a yacht that left the northern Tongan islands group of Vava'u in August, reported on their Web log on August 12 that they saw streaks of light, porous pumice stone floating in the water -- then "sailed into a vast, many-miles-wide belt of densely packed pumice."

They posted photos of huge "pumice rafts" that they encountered after passing Tonga's Late island while sailing toward Fiji.

"We were so fascinated and busy taking pictures that we plowed a couple of hundred meters into this surreal floating stone field before we realized that we had to turn back," wrote a crewman identified only as Haken.

The next day they spotted an active volcanic island, Haken wrote.

He said they could see the volcanic island clearly. "One mile in diameter and with four peaks and a central crater smoking with steam and once in a while an outburst high in the sky with lava and ashes. I think we're the first ones out here," he reported.

There was no official confirmation of a new island, either from Tonga's Ministry of Lands or the Tonga Defense Service.

Separately, fishing boat captain Siaosi Fenukitau reported seeing the volcanic island, the Matangitonga news Web site reported.

Richard Wunderman, editor of the Washington-based Bulletin of the Global Volcanism Network, said "a large pumice raft presumably from Tonga has been sweeping across Fiji, and we are trying to learn about its origins."

A previous eruption in the area generated a small island and similar fields of floating pumice, he said.

Pumice rafts drifted to Fiji in 1979 and 1984 from eruptions around Tonga, and some were reportedly 30 kilometers (19 miles) wide, the Matangitonga reported.