As the world reels from the Parisian terror shootings, Attorney General George Brandis has announced new anti-terror laws that come into effect in Australia this week will help keep the country safe from similar attacks.

The controversial new laws, which have attracted criticism from legal experts, have given the government more powers to detain and punish extremists who fight overseas or plan to commit terrorist acts in Australia.

Senator Brandis said the Paris attacks were an assault on freedom of expression, "the lifeblood of free societies".

"Legislation recently passed by the Parliament has strengthened our ability to arrest, monitor, investigate and prosecute returning foreign fighters and anyone who facilitates or supports that activity," he said in a statement.

"Provisions which came into effect this week continue to strengthen our control order regime, which make it easier for our security and intelligence agencies to monitor people who are a potential threat to the Australian community."

The new laws allow courts to impose control orders that prevent returned foreign fighters from associating with certain people where that would assist in preventing a terrorist attack on Australian soil.

Under the new laws, returned fighters who have intentionally been in a declared area face a maximum 10-year jail sentence.

Returning fighters linked to listed terrorist organisations also face up to 25 years jail.

A new offence, "advocating terror", prohibits promoting or encouraging terrorism and carries a maximum five-year sentence.

Control orders can also now be sought if a court is satisfied the order would assist the prevention of a terrorist act, or where a person has engaged in hostile activities overseas or participated in training with a listed terrorist organisation.

Lower arrest thresholds mean the police can arrest somebody suspected of being involved in terrorism on "reasonable suspicion", which Mr Brandis claimed would allow law enforcement to disrupt plots at an earlier stage.

Courts will have greater flexibility in deciding whether to admit foreign evidence in court proceedings.

Funding will be allocated for another 22 investigators and analysts for the Australian Crime Commission.

Still before Parliament is another Bill that will allow the government to ask telecommunications companies to retain metadata for two years.

The government claims this will help police track and prosecute potential terrorists.

The attacks in Paris have left the world in shocked mourning. (Supplied) (Supplied)