Driver distraction campaigner Russell Keating, who lost a brother and sister-in-law to a crash caused by a texting driver, said the service had come too late.
"It's a bit of a surprise that it's taking this long for them to get something like this out, because it's a wee while now since they've banned it."
He doubted whether people with commonsense had a need for the service.
"Can't they just do it themselves? Surely they don't have to more or less get a machine to stop them," he said.
"When they first brought the ban out, you'd see a lot of people pulled into the side of the road. But it's tended to fall off, and now whether this will help or not, I wouldn't know."
Mr Keating said while he was an advocate for banning cellphones in cars, there were also other distractions drivers needed to be aware of.
Texting and driving has been illegal for more than two years but remains a pressing issue, topping the AA's list of the top 10 driver distractions, released last week.
A recent Otago University study found 54 per cent of drivers on a restricted licence admitted to texting while driving occasionally or more often.
NZTA chief executive Geoff Dangerfield said texting while driving remained a significant and unwelcome cause of too many crashes, despite the ban.
"Nobody is perfect and it is easy to get distracted when driving, so this innovation will help people stay safe," he said.
He encouraged all Vodafone subscribers to use it, and urged other mobile providers to launch similar initiatives.
"Telecommunications has a huge base of customers who use texting to stay in touch. Expanding an innovation similar to DriveSafe can only have a positive impact on safer journeys for all of us."
AA motoring affairs general manager Mike Noon said he welcomed the service as a simple tool that could help drivers leave their phones alone.
"One of the worst things about texting and driving is that drivers know they shouldn't do it but many cases just can't seem to stop themselves when they hear a message arrive," he said.
"The driver can relax knowing the person who texted them has been sent a reply and, as a bonus, it is spreading the message that texting and driving are a potentially lethal mix."
Mr Noon said any distraction while driving was dangerous, but texting was especially bad because people concentrating on messages had their eyes off the road and at least one hand off the wheel.
Vodafone sales director Grant Hopkins said the service was aimed at helping people use their mobiles safely.
"DriveSafe is designed to take the pressure off when you're driving and you get a text message. It lets the sender know that you can't reply immediately, without you needing to take your eye off the road.
"We're pleased to be able to bring innovations like this to New Zealand and hope it will help drivers think carefully about their actions to reduce the road toll."
