TV presenter who knew victim in Sydney siege breaks down live on air

Sunrise presenter Natalie Barr's eyes filled up with tears as she told of the news that 38 year-old Katrina Dawson had been killed.

This is the heartbreaking moment when a newsreader broke down live on air as she revealed a personal connection to one of the victims of the Sydney siege.

Sunrise presenter Natalie Barr's eyes filled up with tears as she told of the news that 38 year-old Katrina Dawson had been killed when the siege ended in the early hours of Tuesday morning.

The Sydney barrister, a mother of three, was the sister of a lawyer friend of Barr's.

Mrs Barr, 46, was co-hosting the Channel Seven show with David Koch when she was overcome by emotion and couldn't continue.

"I'm just finding out that Katrina...Katrina Dawson was the sister of a prominent barrister, Sandy Dawson, who has done some work for Channel Seven," she said. 

"A sister of one of our Channel Seven staff - Sandy Dawson, who I know, and I have friends who know."

She added:"[Katrina] was a mother of three children. We're just finding that out this morning.

"She's the younger sister of the lawyer who does a lot of work for Channel Seven who many would know in Sydney, and that family is suffering this morning, as the others are."

On Monday, lone gunman Haron Monis took a number of hostages captive at a café in Sydney.

The 16-hour siege ended when cops stormed the building. Three people died, including Monis, cafe manager Tori Johnson and Mrs Dawson.

It is believed Mr Johnson heroically lunged at Haron after the terrorist dozed off while Mrs Dawson died as she tried to protect her pregnant friend, reports suggest.

Self-styled radical cleric Monis, 50, was on bail for a string of sexual offences and plotting the murder of his ex-wife before he began his bloody rampage.