Rival telecommunication companies are working together to crack down on international phone scams plaguing the industry.

The NZ Telecommunications Forum (TCF) has today released a draft code of practice for cellphone and landline providers, including Spark, Vodafone and 2degrees, standardising how scam calls are identified and blocked.

TCF chief executive Geoff Thorn said telcos had shared information about scams for several years but the code would help telcos react more quickly to reports of fraud and block calls from numbers used by scammers.

It requires any telco that had confirmed or suspected a new scam to contact the other companies and tell them the number or numbers used by the scammers, what the scam involved and any other available information.

Members of the public can provide feedback on the draft code before it is finalised in July.

Auckland man John Calkin, who was conned out of tens of thousands of dollars in an elaborate internet and phone scam last month, said the introduction of the code was "absolutely splendid".

However, 88-year-old Brian Cotter, who had $50,000 siphoned out of his bank accounts (of which about half was later recovered), was less enthused.

He said he would have hoped telcos already had something similar in place to protect customers because they were big companies with huge investments.

The introduction of the code comes after the resurgence of an elaborate robo-dialling scam earlier this month. Similar scams had been reported in February last year.

Thorn said scammers were using more sophisticated techniques.

"Often, they have access to personal information obtained through third-party sources and may use advanced systems to make it appear as though they are calling from a genuine NZ phone number."

Consumers needed to be vigilant when a caller who claimed to be from a telco provider, IT company or government agency asked for personal or financial information.

"We advise against giving access to personal information over the phone in these instances," said Thorn.

Members of the public could help combat scams by reporting suspicious calls to their service provider.

Spark Home, Mobile and Business' acting chief executive Grant McBeath said although the code would help reduce the volume of scam calls, some would still slip through.

"If people remember one thing, it should be this: Spark will never contact you out of the blue and ask for your personal information. Avoid calling back international numbers you don't recognise and if you are unsure if the call is genuine, the best thing you can do is hang up."

Spark has also today launched a website about scams targeting Kiwis to make consumers aware of the latest techniques used by email and phone scammers.

Spark customers could report new scams by emailing [email protected] and once staff had verified the scam they would update the website.

Netsafe director of technology and partnerships Sean Lyons said it was great telcos were putting competition aside to help all their customers by agreeing to the code.