Wellington, May 13 (IANS): A Royal Commission of Inquiry on Monday began its investigation into the March 15 Christchurch terror attacks that left 51 people dead in two mosques, a New Zealand government spokesperson has confirmed.

The special commission, which is chaired by Supreme Court Justice Sir William Young along with Jacquie Caine, New Zealand's former Ambassador to Chile, will now establish how the investigation will be conducted, Efe news quoted the spokesperson as saying.

"They have the powers to call people to appear before them," said the spokesperson. "They have the ability to look through a lot of material, and their powers are very broad."

"We want them to leave no stone unturned."

The commission, which was set up on April 8, will look into the activities of the alleged Australian gunman, Brenton Tarrant before and after his arrival in New Zealand, his travels and how he obtained weapons and ammunition.

Tarrant, who had no police record, is charged with attacking the two mosques armed with military weapons and shooting at worshippers gathered for the Friday prayers while broadcasting the massacre live on social media.

The commission will also investigate the social networking activities of Tarrant, an former fitness trainer now facing 50 charges of murder and 39 for attempted murder, in addition to his national and international connections.

One of the key tasks will be to scrutinise the role played by New Zealand's Security Intelligence Service, the Government Communications Security Bureau, Police, Customs, Immigration and any other relevant department of the government.

The commission will have to submit its conclusions by December 10.

On its website, the commission says its "purpose is to reassure the New Zealand public, including all Muslim communities, that all reasonable measures are being taken by State sector agencies to ensure their safety and protection".