2degrees says it now has 875,000 people on its network but won't reveal their customers' average monthly spend.
The mobile operator said today its customer numbers had grown from 580,000 last year to 875,656 as of February 1.
2degrees chief executive Eric Hertz said although the proportion of its customers on post-paid plans was on the rise, pre-paid customers still made up "a large percentage of growth".
However, Hertz would not say what each what 2degrees customers were spending on average each month.
"As you can imagine it is improving as we add more of the post-paid customers...it's a highly- competitive issue, it probably says more to our competitors than other readers," Hertz said.
Post-paid customers typically spend more each month than their pre-paid counterparts.
Despite the entry of Telecom's "Skinny" mobile brand, which markets itself as "stripped back" option for those with not much to spend, Hertz said 2degrees still saw itself as a "challenger" brand.
"We have a long way to go...the reality is we've been in business two and half years and the other guys have been in business for 15, 16 or 17 years," Hertz said.