Bill shocks are the biggest cause of complaint for consumers.

Bill shocks are the biggest cause of complaint for consumers.

MORE Australians than ever are dissatisfied with their mobile phone service, according to the Telecommunications Industry Ombudsman's annual report.

The report, released yesterday, shows the Ombudsman received a total of 193,702 new complaints in 2011-12, a decrease of 2 per cent on the previous year. However, complaints about mobile phones increased by 9.3 per cent to 122,834 new complaints.

Ombudsman Simon Cohen said two out of three complaints made to the TIO were about mobile phones, reflecting the rising use of smartphones.

Dissatisfaction is at an all-time high.

Dissatisfaction is at an all-time high.

He said the increased use of smartphones had led to a doubling in complaints about unexpectedly high bills - 15,752 complaints - and a 150 per cent jump in complaints about disputed internet usage charges - 10,556.

The most common complaints included poor coverage, 31,465 complaints, slightly up on last year; mobile billing disputes, up 33 per cent to 13,943; and complaints about the quality of information given to consumers at the point of sale, 20,213 complaints.

Victorians were more dissatisfied with their telecommunications services than any other state, with 56,785 new complaints or 10.6 complaints per 1000 people. This was followed by South Australia (9.9), the ACT (8.9) and New South Wales (8.7).

Residents in Melbourne's CBD and Docklands made more complaints per capita than those of any other postcode in the country. St Kilda, Campbellfield and Doreen were also among the top 10 complaint postcodes in Australia, with coverage being an issue in all three areas.

Optus saw the biggest jump in complaints, up 47 per cent, driven by mobile issues such as faults, inadequate spend controls and disputed internet charges. Complaints against Vodafone also rose, by 11 per cent. However, issues with its network problems reduced significantly. Telstra registered 21 per cent fewer complaints.

The Australian Communications Consumer Action Network's chief executive, Teresa Corbin, said the steep jump in mobile phone complaints highlighted the importance of new spend-management rules, which will be introduced from next year. Under the new Telecommunications Consumer Protection Code, all major providers will be required to send SMS alerts to customers when they have used 50, 85 and 100 per cent of their monthly data allowance. Smaller providers have until September 2014.

''The past year has seen a big increase in the number of people who have made a complaint about an unexpectedly high bill,'' Ms Corbin said.

However, Mr Cohen said the overall drop in complaints was encouraging. "There has been a clear trend, since April 2012, of reduced complaints,'' he said.