Sydney -- Immigrants to Australia will be required to clear an English test under a new citizenship law.

The new test means prospective Australian citizens will have to sit for an internet-based test to demonstrate their knowledge of the English language and basic knowledge about Australia, according to the Australian newspaper.

Australian Prime Minister John Howard said the test would apply to all new migrants who applied to become citizens after being in Australia for four years.

"It is not designed in any way to keep some people out," Howard said.

In September, Howard had defended the new test by saying the government in the past had made citizenship "a little too easy".

Recent terror attacks across major cities of the world had prompted the Australian government to make its immigration and citizenship law tougher.

Already, residency requirements have been sharpened. Immigrants now have to wait at least four years instead of two before being able to apply for citizenship.