Attorney General George Brandis has warned life has become harder for liberal democracies under attack from Islamic extremism.

Asked if Australia was at war, Senator Brandis told the Nine Network: "Absolutely. ISIL have declared war on us."

"We would be fools not to take them at their word and to take whatever steps are necessary to protect our civilisation," he said.

Senator Brandis said Australians may have to "calibrate their attitudes" on privacy.

"There will be occasions in which we will have to accept greater limitations, greater impediments to personal privacy," he told the Seven Network.