The families of the two victims of the Lindt Cafe siege will return to Sydney's Martin Place for the unveiling of a floral-themed memorial, on the third anniversary of the deadly attack.

Hundreds of flowers have been inlaid into the pavement just metres from the Lindt Cafe where the deadly siege unfolded, claiming the lives of cafe manager Tori Johnson and barrister Katrina Dawson.

Designed with approval from the Johnson and Dawson families, around 200 floral cubes have been scattered in a starburst pattern that will illuminate at night.

NSW Premier Gladys Berejiklian will unveil the memorial, designed by Australian architect Richard Johnson, on Saturday morning in the presence of the victims’ families.

The design was inspired by the sea of flowers that blanketed Martin Place following the 17-hour stand-off, which came to a horrific end in the early hours of December 16, 2014.

Eighteen people were taken hostage by self-styled sheik Man Haron Monis when he walked into the cafe on the morning of Monday, December 15.

Police stormed the cafe at 2am the following day in a spray of bullets when Monis executed Mr Johnson. Ms Dawson, a mother of three, was fatally wounded by police bullet fragments.

In a show of solidarity in the days following the siege mourners flocked to the CBD, leaving thousands of bouquets and letters carpeting the pedestrian mall outside the cafe.

The first artist’s impression of the permanent memorial was revealed in 2015 but installation was reportedly delayed by city construction works.

Earlier this year, the results of a long-running inquest into the siege were handed down with NSW Coroner Michael Barnes finding that police waited 10 minutes too long in storming the premises.

The traditional “contain and negotiate” strategy by police was appropriate early on in the siege, Mr Barnes said in May, but it failed as the hours went on.

New Police commissioner Mick Fuller – who was one of the first commanders at the scene – admitted in May tactical officers should have gone in earlier.

By Gemma Najem