Two massive icebergs are threatening research data from a $250,000 worth of NIWA equipment.

NASA satellite images show two large chunks of ice have split from the Nansen Ice Shelf north of Antarctica's Scott Base, and could drift into the path of equipment used to measure ocean temperature and saltiness.

NIWA oceanographer Mike Williams said the icebergs are around 10 kilometres long by about 5 kilometres wide, and could damage NIWA's 600 metre structure used to measure changes in the temperature and saltiness of the ocean, and how that's impacting the ice shelves around Antarctica.

Mr Williams said the icebergs could miss the equipment altogether, they could do some damage to the top of the 600 metre structure, or a third scenario could be more serious.

"The iceberg manages to drag the whole mooring to a location where we can't find it, and that whole mooring is lost.

"What that means scientifically for us is a gap in the record because we won't have an opportunity to put new equipment back in until December or January."