Video provided by Nine News

Chilling footage has emerged showing three would-be terrorists browsing a Bunnings Warehouse while shopping for materials for a Christmas Day killing spree.

Ahmed Mohamed, Abdullah Chaarani and Hamza Abbas were caught on CCTV shopping for bomb-making supplies in Broadmeadows on December 21, 2016.

The trio planned to detonate bombs and behead people in Melbourne's Federation Square after becoming radicalised by Islamic State.

The video was released on Wednesday during a pre-sentence hearing in the Supreme Court after they were convicted on terror charges.

© Provided by Associated Newspapers Limited Footage (pictured) has emerged of Ahmed Mohamed, Abdullah Chaarani and Hamza Abbas shopping for bomb-making supplies in Broadmeadows on December 21 2016 after becoming radicalised by Islamic State

Chaarani was filmed carrying a machete intended for the attacks, while Hamza and Mohamed were captured on CCTV buying ingredients at Chemist Warehouse and Bunnings.

Mohamed requested 700 nail gun cartridges- to make home-made explosives- which are kept locked inside a locked counter of the hardware store.

Bunnings staff raised the alarm after becoming suspicious while scanning their unusual goods at the cash register.

They followed them to their vehicle and wrote down the number plates before reporting the incident to police, who then arrested them hours later.

Chaarani, a twice-convicted terrorist, says he's disgusted by his part in a plot.

He told the court he has 'realised what an idiot' he was for believing he could wage violent jihad after getting caught up in extremist beliefs fuelled by Islamic State propaganda.

He joined his cousins Ibrahim and Hamza Abbas, and friend Ahmed Mohamed in conspiring to develop the potentially deadly plot, for which they'd bought machetes, carried out reconnaissance and built practice bombs.

© Provided by Associated Newspapers Limited Chaarani (pictured) was filmed carrying a machete intended for the attacks, while Hamza and Mohamed were captured on CCTV buying ingredients in Chemist Warehouse and Bunnings.

Chaarani said his father warned him the IS videos and propaganda would land him in jail.

He admitted crying when his father visited him in prison.

'It was the most embarrassing, most humiliating moment of my life,'Chaarani said.

'He said 'you embarrassed me, you shocked me, this is not my son'.'

Chaarani told Justice Christopher Beale, who will sentence him over the plot next month, he had renounced Islamic State and his former extremist jihadi views.

He has begun reforming his views about Islam, including by reading books recommended by imams and through his father.

When asked if he was sorry, Chaarani replied 'you have no idea' and denied he was only speaking up now to get a reduced sentence.

© Provided by Associated Newspapers Limited Chaarani (pictured), a twice-convicted terrorist, says he's disgusted by his part in a plot

'I'm sorry for the havoc I've caused to my family foremost (and) to the legal system,' he said.

Mohamed also renounced Islamic State and his extremist views while in the witness box on Tuesday.

Both are already serving up to 22 years jail for a firebomb attack on a Melbourne mosque in December 2016.

Chaarani said he had pleaded not guilty to that charge on the advice of his lawyers and had not spoken up earlier because he had 'stage fright'.

On Tuesday, Mohamed said he only began to get drawn into Islamic State propaganda because he was embarrassed about not knowing how to pray when he went to mosque with his new practising Muslim friends.

© Provided by Associated Newspapers Limited Mohamed (pictured) also renounced Islamic State and his extremist views while in the witness box on Tuesday

When ringleader Ibrahim Abbas - who is serving up to 24 years after pleading guilty over the plot last year - began to get pushy and nag them about planning an attack, Mohamed felt he couldn't say no.

'I felt like a chicken to say 'no I don't want to do this',' he said.

'I wanted to be the hero of the group ... I wanted to be the cool guy.'

Hamza Abbas did not speak in court, nor has he renounced any extremist beliefs.

His lawyer Felicity Gerry QC said if there was a process to denounce violent ideology 'he would do that', but there was not.

Justice Beale is due to sentence Mohamed, Chaarani and Hamza Abbas on November 29.

© Provided by Associated Newspapers Limited He joined his cousins Ibrahim (pictured) and Hamza Abbas, and friend Ahmed Mohamed in conspiring to develop the potentially deadly plot, for which they'd bought machetes, carried out reconnaissance and built practice bombs