The Telecommunications Users Association is urging the New Zealand and Australian governments to regulate trans-Tasman roaming prices.
The Ministries of Economic Development in New Zealand and Australia are investigating concerns about pricing and a lack of transparency.
One Telecom customer from Upper Hutt says she received an account for $3500 after using the internet for two hours while on holiday in Brisbane.
TUANZ says mobile phone roaming prices are extortionate and a rort and should be regulated.
It says the trans-Tasman roaming market needs regulation as well as warnings for consumers about its costs.
Neither Telecom nor Vodafone wants regulation, with Vodafone saying it would weaken the New Zealand mobile industry.
No quick fix - Joyce
Communications Minister Steven Joyce says the Government is working to bring down the cost of roaming phone charges but says there is no quick fix to the problem.
He told Morning Report that TUANZ is right to a degree and the Government has been working on the issue for some time.
But Mr Joyce said the situation is tricky and involves dealing with governments and companies in Australia and finding a solution which works for everyone.
He said it may take some time to find a solution, and in the meantime, it's important to warn people about the high charges.