Austrian authorities have searched the home of a prominent far-right activist as part of a probe into his ties to the alleged Christchurch mosque gunman, officials said on Tuesday.

Key points: Head of the Identitarian Movement of Austria, Martin Sellner, said police searched his apartment on Monday

Head of the Identitarian Movement of Austria, Martin Sellner, said police searched his apartment on Monday They seized electronic devices after Mr Sellner received money from a person with the same surname as the New Zealand shooter

They seized electronic devices after Mr Sellner received money from a person with the same surname as the New Zealand shooter Prosecutors stumbled across the donation as part of an existing probe into Mr Sellner over possible financial offences

Head of the white nationalist group Identitarian Movement of Austria, Martin Sellner, said on social media that police searched his apartment on Monday.

They seized electronic devices after Mr Sellner received a "disproportionately high donation" from a person named Tarrant — the same surname as the suspected Christchurch shooter.

Austrian Interior Ministry spokesman Christoph Poelzl confirmed on Tuesday that the country's domestic intelligence agency searched the premises in Vienna at the request of prosecutors in the city of Graz.

A spokesman for Graz prosecutors, Hansjoerg Bacher, said prosecutors had stumbled across the donation as part of an existing probe against Mr Sellner into possible financial offences.

"The purpose of the investigation is to examine links between Mr Sellner and the Christchurch attacker," Mr Bacher said.

He declined to confirm when the donation took place, but said it was much higher than other contributions made to Mr Sellner or his Identitarian Movement.

"Most donations were in the area of two to three figures, whereas this donation was in the low four-figure area," Mr Bacher said.

"This made it stand out, and the events in New Zealand put a face to this donation."

Mr Bacher said the investigation against Mr Sellner is based on Austrian anti-terror laws.

The funeral in Karachi of Syed Areeb Ahmed, one of nine Pakistanis killed in the New Zealand shootings. ( AP: Fareed Khan )

"We need to determine whether there is a connection and if so, whether it's criminally significant," he said.

Austrian Chancellor Sebastian Kurz said he had spoken with the Minister of Justice Josef Moser about the raid, and all links to the alleged mass killer will be investigated.

"Every connection between the Christchurch suspect and members of Identitarians in Austria must be cleared completely and ruthlessly," he tweeted.

"It is important that the independent judiciary, with all necessary means and resources, conducts its investigations together with the security authorities and can lift these networks.

"It needs full education about all extremist machinations."

Far-right leader denies link with New Zealand shootings

Mr Sellner denied having anything to do with the March 15 massacre, in which 50 Muslims were killed in the southern New Zealand city.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 35 seconds 1 m 35 s Royal commission to be held into Christchurch terror attacks

Australian Brenton Tarrant was arrested within an hour of the mosque shootings and has been charged with murder.

"I had nothing to do with the attack," Mr Sellner said in a video statement posted on YouTube, adding that he would donate the money to a charitable organisation.

He suggested the reason for the donation might have been to provoke repressive measures against "patriots".

Austrian authorities confirmed the alleged Christchurch shooter toured Austria, Hungary, Romania and Bulgaria during a European trip in late 2018.

They declined to confirm when or whether he met with any far-right activists during his trip.

Some of Tarrant's anti-Muslim views are echoed by the Identitarian Movement.

The group is close to sections of the nationalist Freedom Party, which is part of the country's Coalition Government.

Hundreds of floral tributes have been left near the Al Noor mosque since the Christchurch attacks. ( AP: Vincent Thian )

AP