The US Department of Justice (DOJ) has launched its own investigation into the online music-pricing practices of major record labels.

Investigators are examining whether the major labels have worked together to set prices, the report said.

The investigation is thought to resemble a previous inquiry by New York attorney general Eliot Spitzer, which is still ongoing.

The Justice Department would not name the companies it is investigating. A spokeswoman told Reuters: "The antitrust division is looking at the possibility of anti-competitive practices in the music download industry."

Some subpoenas may have been issued, with others to follow in the coming days, the report said.