Some bungling boating by a group of landlubber drug smugglers led to New Zealand's largest ever haul of methamphetamine, with their fumbling efforts arousing the suspicion of locals, police said Tuesday.

The 494 kilogram haul, with a street value of $347 million, is the largest ever in New Zealand, eclipsing in a single swoop the entire amount of ice seized in the South Pacific nation last year (334 kilograms).

Police said locals found an abandoned boat at remote 90 Mile Beach on Sunday and also reported a group of men had been acting suspiciously in the area in recent weeks.