Allhomes found itself in trouble with the Australian Competition and Consumer Commission for telling 1000 local real estate agents they were being underpaid for their work and pledging to help ''restore reasonable agency fees''.

Allhomes director Peter Blackshaw has given the commission a legally enforceable undertaking after it became concerned that the listings site may have attempted to induce real estate agents to ''arrive at an understanding'' about the level of real estate agents' fees.

The website wrote to local agents in April last year noting their fees were about half of what they were 10years ago and proposing to include a guide to sellers.

A complaint was brought to the ACCC's attention about the email that told agents they had never worked harder for so little reward. ''It has come to our attention that the fees charged by agents today are around half what they used to be 10years ago,'' the email said.

''Clearly agents have never worked harder for so little. Allhomes is committed to restoring reasonable agency fees. We are looking for suggestions.''

The listings site proposed a notice to sellers on the Allhomes' property listings that they should expect to ''pay between 2 and 3 per cent of the sale price of a property for the services of an experienced salesperson employed by a full service real estate agency''.

But acting ACCC chairwoman Delia Rickard said her organisation was worried that the conduct might encourage agents, who are legally free to set their own fees and compete among themselves on prices, to collude to fix fee levels with a ''floor price'' of 2 per cent.

''The ACCC was concerned that such conduct could lead real estate agents to reach an understanding on a minimum price for real estate services in relation to property sales,'' she said. ''This may lead to increases in prices for consumers or a decrease in price competition between those agents.''

Ms Rickard said Allhomes had acknowledged that in sending the email, there was a risk of ''inducing a contravention of certain sections of the Competition and Consumer Act 2010''.

''This outcome demonstrates that the ACCC views all forms of anti-competitive conduct seriously and will act to protect competition in the public interest,'' she said. ''It also reinforces that all businesses, no matter what size, need to be conscious of their obligations under the Competition and Consumer Act.''

As part of the undertaking, Allhomes has agreed not to send or request information to real estate agents about suggested fees.

It has also agreed to send a letter to each of the recipients of its original email, notifying them of the ACCC's concerns and confirming that real estate agents are free to set their own prices.