Two companies that ignored a resident's 'do not knock' sign have been fined by the Federal Court.

AGL South Australia and its marketing company CPM Australia will have to pay a total of $60,000, and other penalties exceeding $1 million have been imposed for use of other unlawful selling practices.

The court said a sales representative ignored a sign on a front door with an image of a fist knocking with a line through it.

It also had the words "Do not knock, unsolicited door to door selling is not welcome here".

The seller still knocked on the door of the house at Elizabeth East in Adelaide in late 2011 and offered the resident an energy supply deal.

The court ordered AGL to pay $35,000 and CPM $25,000 over that matter.

Justice John Middleton found "the contravention subverted both the consumer's desire not to be disturbed or interrupted by sales representatives and the very protections provided to the consumer by the legislation".

On a related matter, he ordered AGL Sales and AGL SA pay combined penalties of $1.5 million for other unlawful selling practices, including making false representations to consumers.

CPM was also ordered to pay $200,000 for its role in that conduct.

The Australian Competition and Consumer Commission said the penalties were another clear warning that businesses needed to comply with laws about making unsolicited approaches.