Sydney barrister Katrina Dawson has been confirmed as the 38-year-old woman who was killed during the siege at the Lindt Chocolat Cafe in Martin Place.

The mother-of-three and rising star at the commercial bar was one of two hostages who was pronounced dead after being taken to hospital after an exchange of gunfire just after 2am on Tuesday.

Ms Dawson, a highly respected barrister from Eighth Floor Selborne Chambers in Phillip Street, was the younger sister of prominent defamation barrister Sandy Dawson and McKinsey & Company director Angus Dawson.

She was married to Paul Smith, a partner at top tier law firm King & Wood Mallesons.

The devastating news has left the Sydney legal fraternity in shock. Ms Dawson was a close friend of barrister Julie Taylor, also from Eighth Floor Selborne Chambers, who was also taken hostage in the Lindt cafe.

There are reports Ms Dawson died protecting the pregnant Ms Taylor, who was taken from the scene on a stretcher.

Ms Dawson, an Ascham old girl, topped the state in the Higher School Certificate in 1994, with a TER of 100, and topped her bar exams.

An alumna of the University of Sydney Law School, Ms Dawson completed her master of laws at the University of NSW. She was called to the bar in 2005 and her chambers are metres from the Lindt cafe.

She has three children aged under 10 - two girls and a boy - the eldest of whom are at Ascham and Cranbrook in Sydney. The youngest, a girl, is four.

Ms Dawson was the daughter of prominent businessman Alexander "Sandy" Dawson, president of the Royal Sydney Golf Club and the former managing director and chief executive of food company Arnott's, and sculptor Jane Dawson.

"Deep sorrow": NSW Bar 

The president of the NSW Bar Association, Jane Needham, SC, said it was "with a heavy heart and deep sorrow" that she informed members of the bar that Ms Dawson had passed away in the early hours of the morning.

"Katrina, together with two other members of the NSW Bar, were held as hostages during the incident at the Lindt cafe in Phillip Street, Sydney, yesterday," Ms Needham said.

"Katrina was one of our best and brightest barristers who will be greatly missed by her colleagues and friends at the NSW Bar. She was a devoted mother of three children, and a valued member of her floor and of our bar community. Our thoughts are with her family at this time, including her brother, Sandy Dawson of Banco Chambers.

"Out of respect to Katrina's family, the NSW Bar Association will be making no further comment at this time."

"Much-loved, outstanding student": Ascham   

Ms Dawson's alma mater said she was a "well-respected and giving member of the Ascham School community".

"Katrina's daughter Chloe is an Ascham student and her younger daughter Sasha starts with us next year," the school said in a statement.

"Katrina attended Ascham from 1981 to 1994 and had a stellar school career both academically and in extracurricular activities. She...was dux of Ascham School and a prefect."

The school remembered her debating prowess, which culminated in her being named debating captain. She also represented the school in hockey and in basketball.

Ascham's head of school, Andrew Powell, said he knew Ms Dawson well and she "is remembered affectionately as an outstanding student who excelled in all aspects of school life and was much-loved by her peers and teachers alike. She was generous in giving of her time and this year Katrina used her skills as a barrister to guide our senior students in preparing for mock trials.

"Our hearts go out to Katrina's entire family, including her husband Paul, and her children, Chloe, Sasha and Oliver. We have been greatly shocked and saddened by this tragic news and will do everything possible to support the family at this terrible time."

"Immense sadness": Cranbrook

In a letter to members of the school community, Cranbrook School headmaster Nicholas Sampson and the president of the school council, Helen Nugent, expressed their "immense sadness" at the death of Ms Dawson.

"Katrina was the mother of Oliver who has just completed kindergarten; Sasha, who attended St Michael's pre-school; and Chloe, a student at Ascham; and the wife of Paul Smith.

"Katrina was the much loved daughter of Sandy and Jane Dawson and sister of Angus and Sandy Dawson, all families who are highly respected members of our school community," they wrote.

"Our thoughts and prayers are with the entire family at this extremely difficult and very sad time.

"We understand that this news will be highly distressing for many of our families and staff.

"Support is available for anyone who wishes it through our school chaplain, Rev Craig Tubman, Rev Michael Jensen (Rector of St Mark's) and head of counselling, Ms Juliet Reiner, via the junior school office.

"St Mark's Anglican Church will be open for private prayer from 2pm this afternoon, for anyone who so desires.

"We thank everyone for their kind offers of support. We will inform you accordingly once the family's wishes are known. Out of respect for the family, the school will be making no further comment at this time."

"Great loss": University of Sydney

Vice-chancellor and principal of the University of Sydney Dr Michael Spence, issued a statement that read: "Our thoughts are with the family and friends of Katrina Dawson, an alumna of the university who tragically died in the events in central Sydney overnight.

"After graduating with a bachelor of arts in 1998 and bachelor of laws in 2000, Katrina Dawson carved out a successful career as a respected barrister, and her death is a moment of great sadness for the University of Sydney and the legal community.

"First and foremost, Katrina's death is a great loss to her family and friends, and I have written to her family on behalf of the university's staff, student and alumni community in this moment of deep shock and sadness for our city."

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