A man who threw a spear at a woman working in a job agency because he was having a 'tantrum' will spend three years and nine months behind bars.

Bevan Bara, 29, stormed in to the job agency Angurugu, a small town on the island of Groote Eylandt in the Northern Territory, on September 22 last year.

He was armed with a 2metre-long 'steel-tipped, shovel-nosed spear' and started brandishing the weapon around, The Supreme Court heard.

Bevan Bara, 29, threw a spear at a woman working in a job agency (pictured)

He was armed with a 2metre long 'steel-tipped, shovel-nosed spear' (pictured)

When the woman saw Bara she got up to leave before turning back to grab her phone so she could call police.

'As she was running to the door you threw the spear at her desk from about 5m away, it skimmed over the top of the desk, dug into some papers and deflected upwards and hit the back wall,' Justice Judith Kelly said.

'She'd been sitting in that chair just moments before you threw that spear and it landed about 2m away from her as she was going through the back door – you could have killed her.'

The woman was so traumatised from the event she had been unable to return to work, the court heard.

He was sentenced to three years and nine months behind bars for his actions

Bara pleaded guilty to a string of charges including recklessly endangering life, stemming from the violent 'tantrum'.

He had said he acted in an aggressive manner because of on 'black magic,' a reason that Justice Kelly slammed as scapegoating.

'It seems to me that you actually behaved like a two-year-old having a tantrum only much, much more dangerous because you're a grown man and you were armed with potentially lethal weapons.'

Bara will be eligible for parole after serving 23 months.