Hundreds of floral tributes have been left in Sydney's Martin Place for the victims of a 16-hour siege which ended when police stormed the Lindt Chocolate Cafe early this morning.

"It is almost as if a beating heart of the city is being put in place. It is showing us that this city is alive," Premier Mike Baird said after laying some flowers.

Barrister and mother of three Katrina Dawson, 38, and Lindt cafe manager Tori Johnson, 34, were killed in the siege, along with 50-year-old gunman Man Haron Monis.

"Our hearts go out to the families of Katrina Dawson and Tori Johnson. These were decent, good people, who were going about their ordinary lives," Prime Minister Tony Abbott said.

Look back at how events unfolded on our blog.