New Zealand police arrested two people Thursday over online threats against two Christchurch mosques targeted in a white supremacist attack two years ago that claimed the lives of 51 Muslims.

Police in the South Island city announced the pair's arrest as Christchurch prepares for the second anniversary of the horrific attack on March 15, 2019.

They said no charges had yet been laid and did not provide further details.

The Al-Noor Mosque in Christchurch has been a target of online threats
The Al-Noor Mosque in Christchurch has been a target of online threats AFP / Sanka VIDANAGAMA

"We take all threats of this nature seriously and we are working closely with our Muslim community," police said.

"Any messages of hate or people wanting to cause harm in our community will not be tolerated -- it's not the Kiwi way."

In March 2019, Australian national Brenton Tarrant targeted men, women and children who had gathered for Friday prayers in Christchurch, killing 51 and injuring dozens more.

The self-proclaimed white supremacist was jailed for life last year without the possibility of parole.