The country's most popular mobile phone network has lost up to 50,000 customers in a span of three months.
However, it continues to have a firm advantage over close rivals Telecom and 2degrees.
Vodafone Group's financial results show a dramatic drop in customer numbers between July 1 - when the company had 2,370,000 customers - and September 30, when that figure fell to 2,320,000.
The loss of mobile customers is something of a trend for Vodafone NZ this year.
Between April and July it shed 40,000 customers - on top of losing 9000 customers between January and April.
Of the 2.3 million customers Vodafone had at September 30, 66.2 per cent were prepaid customers - down from 66.5 per cent at July 1.
That suggests a number of the customers Vodafone lost were on prepaid accounts, which typically bring in less revenue for a telco.
Meanwhile, Telecom's latest figures revealed it had around 1.6 million mobile connections following the close of its ageing CDMA network, and 2degrees announced in August it had over one million mobile connections.
Yesterday, Telecom spokeswoman Joanne Jalfon said the company could not give any other detailed customer figures until its half-year result was known.
Spokeswoman for 2degrees Charlene White said the company, too, could not reveal any figures and would not comment on Vodafone's losses.
The 2degrees network's popularity, however, seems to be increasing. The company said in August that it had hit the milestone of a million customers.
Chief executive Eric Hertz said at the time that the introduction of several initiatives - including carry-over minutes, long-life broadband and "listening to what people wanted" - had seen more and more people signing up.
Another unique feature that had been popular with new customers was being able to bring existing mobile numbers to the network.
Mobile network wars
Vodafone: 2.32 million customers
Telecom: 1.6 million
2degrees: 1 million.