"Net immigration was weaker than expected in December, breaking a three month run of positive inflows," said Westpac Banking economist Felix Delbruck in a note. "It's too soon to say if the recent improving trend has stalled - this may just be monthly volatility."
Today's figures also showed flat visitor arrival numbers, with the number of short-term visitors falling 0.1 per cent to 364,000 in December and down 1.4 per cent to 2.56 million on an annual basis. The number of Chinese visitors climbed 35 per cent on the year, with Asian arrivals up 11 per cent to 511,000.
European visitors fell an annual 14 per cent to 406,000, while Australian arrivals were flat on the year at 1.16 million.
The figures also showed more New Zealanders were taking advantage of the strong kiwi dollar, with more overseas trips. International trips by locals rose 4 per cent to 2.17 million in 2012, with the biggest increase in the number of travelers heading to the US. The kiwi recently traded at 83.90 US cents.