A silver fern has been projected onto the Sydney Opera House as a symbol of solidarity for the people of New Zealand following the Christchurch terrorist attack.

Key points: Ms Berejiklian said the illumination represented "solidarity, support and respect" with New Zealand

Ms Berejiklian said the illumination represented "solidarity, support and respect" with New Zealand She said the loss was felt deeply in Australia, "given the closeness of our two countries"

She said the loss was felt deeply in Australia, "given the closeness of our two countries" An Australian has been charged with murder over the terrorist attack

The sails of the Opera House were lit up with the New Zealand symbol on Saturday night, a day after Muslims were massacred while worshipping at mosques in Christchurch.

New South Wales Premier Gladys Berejiklian said the silver fern illumination represented "solidarity, support and respect" after 50 people were killed when an Australian alleged gunman stormed two mosques.

Ms Berejiklian said the display demonstrated the state's unity and compassion towards everyone affected by the attacks.

"We feel the loss in Christchurch especially deeply given the closeness of our two countries. It is as though this has occurred on our own soil."

In Christchurch, mourners laid flowers at cordons near both mosques, while hundreds more gathered at an official area set up for people to pay their respects in the city's botanic gardens near the hospital where dozens of people are being treated for injuries.

The accused gunman, 28-year-old Brenton Harrison Tarrant, was remanded in custody after he appeared in a Christchurch court on Saturday charged with murder.

AAP