Customers of smaller Australian telcos are set to begin receiving the same usage alerts provided to customers of Telstra, Optus and Vodafone.

From Monday, all telcos must alert users within 48 hours when they’ve used 50, 85 or 100 per cent of their data or phone and text allowances.

The three biggest operators – Telstra, Optus and Vodafone – already send such alerts, usually via text message, but many smaller operators do not.

The universal notifications are designed to help consumers avoid “bill shock” – the excess charges slugged on users who exceed their monthly allowances.

They are the final protections to kick in as part of the Telecommunications Consumer Protections (TCP) Code, which was registered precisely two years ago in response to concerns that customers were being ripped off.

In addition to usage notifications, the code has strengthened regulations on advertising, including limits on the use of words such as “cap”, “free” and “unlimited”.

It’s also standardised billing practices and streamlined the complaints-handling process, with urgent complaints required to be resolved within two days.

According to the Australian Communications and Media Authority, which registered and enforces the code, the measures are working.

The industry ombudsman received an average of 402 complaints per day in the first three months of the year, down from 573 per day in the equivalent period in 2012, before the code was registered.