Vodafone NZ is increasing the daily cost of its roaming plan from $5 a day to $7 a day from July 11 - a 40 per cent increase.
The telco says that at the same time, it is increasing the number of countries covered by the deal from 70 to more than 100.
The move follows a $3 price rise across all of Vodafone's broadband plans in the New Year, which it said was the result of accumulated price rises by wholesaler Chorus.
Some customers will also be able to get a refund if they don't like the roaming increase.
A statement on Vodafone NZ's website says, "If you are on a mobile plan governed by the Consumer Terms, and believe that Daily Roaming for $7 a day has a detrimental impact on you, you are entitled to cancel your contract without incurring an early termination charge. If you are paying off a device on an Interest-free Payment, that device will still need to be repaid as per your Interest-free terms.
"If you are on any other plan and believe Daily Roaming for $7 a day has a material detrimental impact on you, you are entitled to cancel your contract but you must pay an early termination charge. You are also required to pay the outstanding amount on any device you are paying off on Interest-free as per your Interest-free terms."
Vodafone is in the process of selling its New Zealand operations to Infratil and Brookfield.
The telco said last month that its branding and global roaming and other perks of being part of an international group would remain under its new ownership through a licence fee arrangement.
Roaming will now cost more from around the time the deal is expected to close, but a spokeswoman told the Herald the price rise is not related to the sale in any way.
So why the price increase?
The spokeswoman said, "Vodafone launched Daily Roaming over five years ago and since then have made numerous improvements to the service, including expanding it from 23 destinations to now over 100. Included in the latest round of new destinations are Vietnam and Cambodia, which are hugely popular with Kiwis.
"We have not increased the price since launching the service despite mobile data usage having tripled and the costs to Vodafone being widely variable across regions. We have retained one fixed price for every destination for the sheer simplicity of it for customers. They don't have any set-up hassles and don't need to try to predict their usage by buying bundles. We believe our roaming offer provides an easy-to-use, highly competitive service for our customers."