"We are seeing considerable growth in mobile expenditure, with the first half of 2012 delivering the total amount spent in 2011," she said.
Mobile ad spending of $650,000 in quarter two was 156 per cent higher than for the same period last year.
This growth was probably a result of the increase in specialist mobile media companies new to the kiwi market, a rapid rise in smartphone penetration, and a rise in New Zealand-based apps and publisher sites, said Vodafone commerce manager Bridget Gallen.
All in all, mobile had become a more attractive media channel to marketers, she said.
"While mobile ad spending in New Zealand is well below what it is in other markets, we anticipate that this recent growth should continue as it has in these other markets."
Across the entire online ad market, growth levels in quarter two slowed to 7.11 per cent year-on-year.
Advertisers had not rushed as they usually did to spend marketing dollars at the end of the financial years, said IAB NZ chair Liz Fraser.
"Leading up to the end of June, often marketers have a bit of loose change that they want to offload.
"However, my belief is that cost savings in businesses were found well before the start of quarter two."
The largest year-on-year growth came from classifieds, expanding 19.8 per cent to $27.82 million.
"This is now two consecutive quarters for the classifieds category to see such high growth", said Fraser.
In display advertising, the highest spend came from travel and accommodation providers, reflecting the sector's recognition that people were going online to research and purchase holidays.