A telecommunications watchdog is calling for a cap on mobile global roaming charges after a New Zealand businessman was billed more than $10,000 for internet access in Australia.

Paul Ballentyne, who runs a website selling Kiwiana art, had been using global roaming to access the internet for work while holidaying with his family, One News reported.

When the internet stopped working he called Telecom and was informed that his account had been shut down due to an unpaid roaming bill of $10,576.

The inflated bill was the result of a technical glitch and the same amount of use in New Zealand would have cost about $65.

Customers should be warned that they could incur huge costs from using global roaming, he said.

Telecommunications Users Association spokesman Ernie Newman said global roaming costs were high because there was no regulation.

Charges were incurred offshore and passed on to mobile phone companies, which then passed them on to customers.

It was unclear where in the chain the price-hikes were introduced, and authorities were powerless to cap prices, Mr Newman said.

"It's an absolute rort because the companies do very little to actually forewarn customers about the very, very, very high costs," he said.

"Many of these charges are way beyond what can rationally be justified."

Telecom spokesman Mark Watts said there was potential for roaming prices to move, but prices were dependant on contracts with network operators in other countries.

The OECD and Apec were reviewing roaming rates.

- NZPA