National Party leader Simon Bridges has condemned the Christchurch massacre saying it is a "horrible day in New Zealand history".

Gunmen have opened fire at mosques in Christchurch, with reports of up to 30 people killed. Four people are in custody - three men and one woman.

A number of IEDs that were attached to vehicles in Christchurch have been defused by the Defence Force.

Speaking to Mike Yardley, Bridges said he condemns the attacks and is shocked.

"The people of Christchurch, our Islamic community...no one should live in fear no matter their race, religion, or politics. It's a shocking, awful day for New Zealand."

The National leader said there will be serious questions over the attack, but they aren't or today.

"We know there are people in hospital with their families. There are people all over Christchurch worrying."

He said we can't change our way of life because of horrible events like this.

"I don't want to change the way my family and I, and New Zealand families go about their lives as a result of a dastardly, evil act."