Home Affairs Minister Peter Dutton said Australia’s security agencies are very concerned about retaliatory or copycat attacks in the wake of Friday’s Christchurch terror attack.

Speaking on Today, Mr Dutton confirmed national security officials will be holding urgent briefings on the issue but assured Australians authorities were working around the clock to keep them safe.

“Obviously, all of our agencies have been very concerned about those very real prospects and they've been working day and night to make sure that we keep Australians safe,” Mr Dutton said.

The shootings in Christchurch shocked New Zealand and the globe. (AP)

“But they've worked very closely from the moment this atrocity occurred with their New Zealand counter parts. And they will continue to do that.”

Australian man Brenton Tarrant allegedly opened fire on worshipers on Friday, storming Masjid Al Noor and Linwood Masjid, killing 50 people.

Mr Dutton said the government will also provide whatever resources are needed and will respond to any risk of attacks accordingly.

Home Affairs Minister Peter Dutton assured Australians the government was working hard to keep people safe. (9news)

“The important point here is if you look at this individual, he had been in Australia I think for 45 days over the last three years, travelled extensively over the last almost decade,” he said.

“So we need to be realistic about the work of the agencies. There are millions of posts, millions of tweets, messages etc that need to be trawled through.”

People pay their respect to the victims of the Christchurch mosques shooting. (PA/AAP)