Christchurch mayor Lianne Dalziel says the city is in a state of shock.

Forty people have been killed and 20 people hurt after four gunmen stormed two Christchurch mosques in the worst terror attack on New Zealand soil.

Dalziel told Chris Lynch that the attack left her lost for words.

"It was so shocking that there are no words taht can truly describe the horror of what has unfolded today. It's unbelievable that it could happen in Christchurch and unbelievable that it could happen even in New Zealand."

She says that when she heard that the gunmen chose this specific mosque and moved to Christchurch to take out this attack, she found it unbelievable.

"It's unspeakable. I cannot speak to the horror of what that represents."

She says you can't ask questions as to why as there is no rationale behind these attacks.

Dalziel says the attack was clearly calculated and pre-meditated on a specific community.

She thinks that in order for us to get through this is for us all to reach out to each other.

"Checking up on friends, making sure people you know and even people you don't know, just caring for people right now."

Dalziel says that this attack is motivated by the most base motives and we need to speak out against this acts of hate.

She says that Christchurch will never forget this day.

"The 15th of March will just be one of those days that lives on forever in our memories as a city."