(AP) – Strong westerly winds in the southern Pacific Ocean have driven scores of icebergs originally headed toward New Zealand to the east, away from the country, an oceanographer said Tuesday.

A shipping alert was sent out last week and maritime authorities have been monitoring the iceberg flotilla as it drifted north from Antarctica toward New Zealand’s South Island.

The nearest one, measuring about 330 to 660 feet (100 to 200 meters) long, was 160 miles (260 kilometers) southeast of New Zealand’s Stewart Island a week ago.

Australian glaciologist Neal Young said satellite imaging shows no sign of any icebergs northeast of Auckland Islands, 250 miles (400 kilometers) south of New Zealand.

“If ice is there, it’s below 500 feet (150 meters) in length,” the smallest size detectable on satellite images, Young said.

Scientists say the current flotilla of icebergs likely split off Antarctica in 2000 when parts of two major ice shelves – the Ross Sea Ice Shelf and Ronne Ice Shelf – fractured. The Ross Sea Ice Shelf is the size of France and is also widely believed to be the origin of the 2006 icebergs.

Icebergs are routinely sloughed off as part of the natural development of ice shelves.

The latest appearance of the bergs in waters south of New Zealand depends as much on weather patterns and ocean currents as on the rate at which icebergs are calving off Antarctic ice shelves.

Rodney Russ, expedition leader on board the Spirit of Enderby eco-tourism vessel east of New Zealand, said they had earlier spotted two big icebergs north of Macquarie Island and also sighted two fishing boats working south of Auckland Islands.

While the vessel has a fully ice-strengthened hull, it has up to three sailors on permanent watch in iceberg-affected ocean, a constant radar scanning and also uses powerful searchlights during the short, six- to seven-hour nights, he noted.

“It would be a foolhardy captain who would come down here and not step up the (iceberg) watch and increase the lookouts,” Russ said.