Men accused of Christmas Day terror attack intended 'violent jihad,' Melbourne court told

It's obvious that three men accused of plotting a Christmas Day Melbourne terror attack wanted to "wage violent jihad" against non-believers, a jury at the Supreme Court of Victoria has been told.

Their plans were well and truly on foot by late October 2016 and in the following two months they bought bomb-making materials and machetes and scouted CBD locations, crown prosecutor Nick Papas QC says.

After weeks of evidence, the Crown is summing up its case against Hamza Abbas, 23, his cousin Abdullah Chaarani, 27, and Ahmed Mohamed, 25, who all deny knowledge and involvement in planning an attack on Federation Square two years ago.

Hamza's 24-year-old brother Ibrahim Abbas has already pleaded guilty to preparing for the attack and gave evidence he was a leader trying to recruit others for his cause.

But Mr Papas urged jurors today to reject that suggestion and find Ibrahim was not a leader, but a co-conspirator in a plan to "wage violent jihad against those they believed to be disbelievers".

He replayed CCTV of the foursome meeting at Federation Square days before their alleged attack was to take place.

An extremist video found on Chaarani's phone showed pictures of Federation Square, St Paul's Cathedral and the Yarra River and called for watchers to "come to martyrdom".

"The Crown says they're talking about this as a great place to cause lots of mayhem and injuries, lots of innocent people to be killed, the more the better," Mr Papas said of the CCTV.

Ibrahim described the gathering as a spontaneous drive to the city to get ice cream, during which he suggested the location might be good for an attack.

But Mr Papas said that contention was "ridiculous", and even Mohamed's wife had sent him a text that afternoon saying "I don't appreciate how secretive you're being".

Mohamed and Chaarani are accused of working on plans from October 2016, when it's alleged Mohamed saved a link to the Al Qaeda magazine article "How to make a bomb in the kitchen of your mom" and that he and Chaarani searched for information on sparkler explosives.

Mohamed and Ibrahim also purchased materials including light globes, pipes and Ramset cartridges, the prosecution argues.

It's alleged Hamza became involved from December, but did so with full knowledge of the sourcing of materials and other preparations.

He joined Mohamed, Chaarani and Ibrahim on the final of three trips to Clonbinane, when it's claimed they tested a bomb in a state forest.

When that failed it's alleged they moved to a new bomb-making method involving hydrogen peroxide, which Hamza and Mohamed were seen purchasing on CCTV.

"The Crown says (they thought) 'one way of setting off a bomb has failed, let's try the other way'," Mr Papas said.

The Crown closing continues.