Shockwaves from a large French nuclear test in the South Pacific were detected Thursday by New Zealand scientists based in the Cook Islands, officials said.

The scientists said they were almost certain the explosion took place on Fangataufa Atoll, in French Polynesia, and not at the usual Mururoa Atoll testing site.If so, it would be the first time since 1975 that the French have used Fangataufa for nuclear testing, according to a statement issued Thursday by Russell Marshall, New Zealand's minister for disarmament and arms control.