Key Points:

A proposed ban on drivers using hand-held cellphones has been announced by the Government in a bid to reduce road accidents.

The proposed amendment to the Land Transport (Road User) Rule 2004 is scheduled to be released for public consultation in August and planned to come into effect on July 1 2009.

Transport Safety Minister Harry Duynhoven said drivers would still be able to use hands-free phones and two-way radio under the proposed ban.

An exception would also be made for motorists calling 111 when it was "unsafe or impractical to pull over to make a call" in a genuine emergency.

Though Mr Duynhoven has previously advocated a ban, Cabinet has resisted it on the grounds that other driving distractions could be equally fatal.

But he today said the culture of cellphone use had changed since the Government first considered a ban in 2004.

"The number of reported crashes involving the use of mobile phones has more than doubled over the last six years, with research showing that using a mobile phone while driving increases the risk of being involved in a crash by up to four times," Mr Dynhoven said.

He said "social conventions", meant drivers were more likely to respond to text messages immediately rather than waiting until they had reached their destination.

"This is only going to worsen as access to enhanced technology is increased."

Under the planned amendment, the use of Blackberries and Personal Digital Assistants while driving would also be banned.

Vodafone and Telecom have previously backed a ban, saying the message it was dangerous to text or talk on a hand-held phone while driving was not getting through.

Vodafone today gave its support to the Government's proposal, saying it would make roads safer.

Chief executive Russell Stanners said drivers should not use hand held mobile phones and should ignore text messages.

"We believe most people already know that its wrong. We hope this will be a tipping point to change their behaviour," Mr Stanners said.

He said his company had an internal policy not to use hand-held phones, send or read texts or email while driving.

Between 2002 and 2007 there were 411 crashes involving injury and 26 fatal crashes where the use of mobile phones or other telecommunication devices was identified as a contributing factor.

Transport Minister Annette King said at least 45 countries had already banned the use of mobile phones while driving.

"While awareness campaigns would continue to focus on the wider issue of driver distraction, the Government's decision to consider a ban on cellphone use recognised the unique nature of mobile phone distraction," Ms King said.