This is the reality that will guide mobile phone chat rooms from next month. Phone firms were told in June to implement safeguards to protect young chat room users from pedophiles, bullies and pornography.

Guidelines released yesterday by the Australian Communications and Media Authority suggest chat rooms employ legions of human moderators to intervene, block or modify messages being sent between users.

Personal information that pedophiles could use to target teenagers should be removed.

Users who requested contact details from others should be warned or barred, and phone numbers and numbers longer than three digits blocked.

The authority said the personal nature of mobile phones meant parents were in less of a position to supervise.

"Although most people in mobile chat rooms are friendly and polite, some can be unfriendly and rude and a small number are exploitative and predatory," said the authority's chairwoman, Lyn Maddock. "Pedophiles have been known to use chat rooms to initiate contact with children."

The guide is not compulsory, but the big carriers plan from next month to have the rooms monitored by staff of a Melbourne firm, Jumbuck. Because it is not yet possible to determine who is a child and who is not, all users will be subject to scrutiny.

Jumbuck already provides a software filtering service to Telstra and Optus and monitors for overseas phone companies.

Olivia Hilton, Jumbuck's chief operating officer, said 35 staff read a million messages a day, within two minutes of being posted. "Moderators sit in front of a PC and monitor every message that comes through. They are short in length, and can be 10 characters."

Jumbuck also monitors chat rooms in the US, where just mentioning your clothes size results in a warning and message deletion. However, Ms Hilton conceded talking about clothes was a large part of teenage girls' lives.

She said she supported the Australian guidelines, but was concerned that restricting and banning users might undermine "a fun and frivolous activity". Vodafone was the first firm to introduce human monitoring but this year it shut down its chat rooms. It said yesterday it would only reopen them when age verification technology was developed.