Market researcher IDC has accused the three major Australian mobile phone carriers ­ Telstra, Optus and Vodafone ­ of "stringing" Australian iPhone users with their data download pricing plan.

It says in some cases monthly data limits can be reached in less than a minute ­ and "unwary users could find themselves being stung in excess of A$1000 per gigabyte for excess data usage.

IDC's report is titled Careful Where You Click: iPhone 3G Hits Australian Market ­ and Consumers' Credit Cards.

It says that while Australians are able to obtain a 3G iPhone on a plan for as little as A$816 or A$729 prepaid, "the overall value in Australian iPhone 3G pricing plans leaves a lot to be desired and comes with very costly excess usage charges."

IDC reckons it's a "shame" that Apple has so far shut out Hutchison Telecoms' "3" operation from iPhone sales. Three, it says, has consistently led the way with increased value plans and lower cost mobile services; and 3 Hong Kong offers the best value iPhone plans in the Asia-Pacific.

The "3" Honkers deal includes 500 minutes of national voice calls, 2000 minutes of on-net calls, unlimited SMS and 500MB data for the equivalent equivalent of A$49 a month, including handset payments. "Given the opportunity, 3 Australia would no doubt offer market leading value through compelling plans," says report author Mark Novosel.

(Hutch Oz has been urging users to petition Apple to give it access to iPhone and promising better deals).

IDC is especially critical of Telstra's initial plans, some of which offer "a trivial 5MB of data per month ­ which can be consumed in less than one minute ­ downloading a single song leaves consumers with excess usage charges of $1/MB".

However is says that less than two weeks after launch, Telstra has revamped its plans to include a mandatory data bundle.

Of the three carriers, Novosel reckons Optus has the widest selection of options, provides the most flexibility and arguably the best overall value for users.

By contrast, "Vodafone's iPhone 3G pricing has gone against the company's recent trends, such as pioneering moves by slashing mobile broadband to $39 for 5GB, which resulted in a unanimous downward shift in mobile broadband pricing across the board," says Novosel.