The Attorney General Christian Porter has defended the State Government's proposed anti-association laws, saying they will target criminal organisations.

The laws would give police the power to ban people from associating with certain groups, and from visiting some establishments

Perth lawyer Tom Percy QC was one of 500 people who attended a rally against the proposal yesterday, saying it would erode basic civil liberties.

But, Mr Porter has told ABC Local Radio the laws would only be used to combat organised crime.

"You have to show to the relevant standard that an organisation, in this case we say that there are criminal organisations in the form of bikie clubs, that they are a criminal organisation," he said.

However, Mr Percy says the laws are an attack on basic civil liberties and will not just target bikie gangs.

"It's about basic freedoms, but specifically the right to associate with whom you want to associate, it's also about whether the government has the right to take that freedom from us. I say, it hasn't," he said.

He says the laws are draconian and demonstrate the need for a Bill of Rights.

"The fact that this legislation could even be contemplated that we can even think about it in a civilised country in 2010, demonstrates the glaring need in Australia for a constitutional Bill of Rights," he said.