A Melbourne man has revealed that accused Christchurch gunman sent him death threats more than two years before the mosque shootings.

The man had reported the threat to Australian police in 2016 – and was only told to block the alleged gunman on Facebook.

The man said the accused sent him a death threat after he had criticised the United Patriots Front (UPF).

He kept screenshots of the threats made in August that year, the ABC reported.

The contact took place via Facebook messenger and the accused mosque gunman told the man: "I hope one day you meet the rope".

The Australian-born accused gunman defended the UPF, which is an anti-immigration group, as "the leading ethno-nationalist group within Australia".

"When you speak against the UPF you speak against my right to a home for my people and my culture," he wrote.

"This marks you."

The accused gunman warned the man to "choose your words carefully" and "think of who you insult".

"I hope you one day see the light and if you are a Marxist I hope you one day meet the rope."

The recipient of the threat reported the incident to police in September 2016.

He provided a copy of the conversation and told officers he believed the accused gunman was dangerous, ABC reported.

The man said police did not take a formal statement – and instead told him to block the threat maker on social media.

After the Christchurch mosque attack that claims 50 lives the man was shocked to discover the identity of the alleged culprit.

"I feel a sense of guilt and have been beating myself up," he told the ABC.

"But at the time I thought I was the only one in danger."

The accused Christchurch shooter appeared in the High Court at Christchurch last Friday.

He faces 50 charges for murder and 39 charges for attempted murder.

He has not entered a plea over his alleged attack on the two mosques, one in Deans Ave and the other on Linwood Ave.

Thirteen people are still in hospital weeks after the shooting.