REGIONAL restrictions on DVDs could be an anti-competitive practice and a breach of the Trade Practices Act, the Australian Competition and Consumer Commission has warned.<P>DVD hardware and software makers encode DVDs to play in one of six regions around the world as a means of controlling release dates and fighting piracy.<BR>Australia ? along with New Zealand, Central and South America ? is region four. The United States is region one and Japan is region two.<P>The restrictions mean that Australian consumers wanting to buy imported titles must buy a DVD player from the appropriate region or modify their machines. Legal advice obtained by The Australian IT is that it is legal to put a chip or smart card in a machine to play imported DVDs, as long as the it does not also allow the machine to play copied discs.<P>But such a change usually voids the product warranty.<P>ACCC chairman Allan Fels said the commission was investigating whether restrictive region coding breached the Trade Practices Act.<P>"If the manufacturers have an agreement to do that, it looks like an anti-competitive agreement breaching not only Australian law but laws in other countries," Professor Fels said.