Sunrise presenter Natalie Barr broke down live on air while revealing her personal connection to the death of a Sydney siege hostage.

The Channel Seven personality was overcome with emotion as she revealed 38 year-old Katrina Dawson had been killed when the siege ended in the early hours of Tuesday morning.

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

The 46 year-old TV personality was co-hosting the coverage with presenter David Koch when she was unable to continue. Breaking down in tears, she explained her connection to the family. 

'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 went on to explain, '[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.'