A barrister who knew Man Haron Monis says he spoke to the gunman in the Lindt cafe the morning of the siege in Sydney’s Martin Place, and that he appeared “very cool, calm and collected”, an inquest hears.

The NSW Coroner is investigating the deaths of Monis and hostages Tori Johnson and Katrina Dawson in the siege on December 15, 2014.

Barrister Michael Klooster, who worked on the eighth floor of the Lindt cafe building said nothing seemed wrong when he spoke to Monis in the cafe in the morning.

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“For someone who was about to do what he did he was very cool, calm and collected,” he said.

“It was like talking to someone at a bus stop.”

Mr Klooster said he had gone into the cafe to get coffee about 9.20am and Monis called him over.

“It appeared to me he was quite surprised to see me,” Mr Klooster told the inquest.

He said he knew Monis because he had acted for him in a Family Court access matter in September 2014 when Monis applied to get custody of his children.

Sydney siege victims Katrina Dawson (left) and Tori Johnson.

The barrister said Monis lost the application but when he acted for him he appeared to “understand the process” and was intelligent and aware of what was going on.

Mr Klooster said that on the day of the siege, Monis asked him if he wanted to have a coffee to discuss appeal avenues.

But Mr Klooster said he rejected the coffee invitation because he had to be in court in 10 minutes.

The barrister said Monis had worn white religious robes when he encountered him for the Family Court matter but on the day of the siege he looked very different because he was wearing a baseball cap and jeans.

Mr Klooster said after seeing media reports of the siege later in the day, he phoned Federal Police and told them he had seen Monis in the cafe earlier and that he might be a person “known to them”.

He said police called him back and took a statement from him.

Another witness Rosemary Birt ,who was outside the cafe, told the inquest she called triple-0 after seeing Monis take a gun out of a plastic bag.

Ms Birt said she was scared and fumbled typing in the security code to unlock her phone.

The inquest was on Tuesday shown footage of the final moments of the stand-off as police stormed the cafe and fired numerous shots at Monis.

It showed Monis firing a shot at six hostages as they made their escape from the cafe.

The inquest continues.

– ABC