Local telco subscribers were being ripped off on current data plans offered by the country's three major players, the Australian Communications Consumer Action Network (ACCAN) said on Monday.

While Optus, Telstra and Vodafone did not jack up on their price offering per subscribers' plan, consumers are getting less when compared to the more generous packages that companies have dangled in the previous years, ACCAN spokeswoman Elise Davidson told The Sydney Moring Herald on Monday.

"In most cases, plans are staying at the same price point but you get less included, especially in terms of data," Ms Davidson said.

All three companies have slashed down the amount of data they provide for customers every month and these adjustments were somewhat cloaked by the decision to keep the price with the 2011 levels.

The collective move was implemented by the telcos as government data showed that mobile computing in Australia, which is especially true for smartphone users, climbed up by at least 32 per cent in the first half of 2012, with the base of comparison figures that the Australian Bureau of Statistics (ABS) had collected in December 2011.

Parallel to that is ACCAN's records that showed phone bill disputes ratcheted up in alarming pace in the past year - by up to 150 per cent, Ms Davidson said, with smartphone owners emerging as the hardest hit because of their tendency to go online almost at all times.

Data download trend in domestic setting, in short, is in direct contrast with the claims of telcos that subscribers have been downsizing the amount of data they consume every month.

Particularly questionable is Optus claims that most smartphone users make do with average data downloads of more than 500MB each month, which Ms Davidson is inconsistent with publicly published data on Australia's mobile computing habits.

ACCAN also lashed out at Telstra and Vodafone for their respective service plan reconfigurations that avoided slapping customers with price increases but silently reduced data access by as much as 40 per cent per billing cycle.

Whatever bonus, freebies and perks thrown in by service providers to their advertised plans have been negated by the data cutbacks, the peak body for telco customers said.

The trick is in line with the usual practice of food manufacturers, Ms Davidson said, which "decrease the amount (of food) in the box, thereby increasing their profit, and hope their customers won't notice."

In the same way for local telcos, as demands rise for quality network services, actors were hard-pressed to pour investments to fund for infrastructure and technology upgrades and try to mitigate the burden of higher capital expenditures by pushing out not-so generous data package plans.

"Lowering the included data that's available on plans is a good way to reduce congestion while they're scrambling out with these upgrades to the networks," Ms Davidson explained.

"All of the networks, to some extent, have been caught up by the demand for data. There is so much demand for it that it's become more valuable," Fairfax reported her as saying.