Marquee to be erected for siege tributes ahead of rain forecast

Volunteers have begun the delicate process of collecting floral tributes for the Sydney siege victims ahead of a forecast for rain.

Notes, messages and cards will be preserved when the existing blanket of flowers at Martin Place is taken down and composted on Tuesday.

Parts of the tribute for Lindt cafe manager Tori Johnson and barrister Katrina Dawson will remain under a marquee.

The removal of parts of the makeshift shrine has been designed to preserve the messages and not to discourage people from paying their respects at Martin Place, a spokeswoman for the NSW premier said.

The families of the victims had been consulted about the decision and would be involved in the establishment of a permanent memorial, the spokeswoman added.

It is estimated there are about 95 bunches of flowers per square metre at Martin Place and up to 100,000 bouquets.

An army of volunteers from the Red Cross, Rural Fire Service and State Emergency Service will help collect the flowers, which will be used for clean mulch at a site to be chosen by the victims' families, while chaplains remain to counsel visitors.

Condolence books will also be available at the Sydney Opera House and NSW Parliament House until the end of January.

They will be bound in several volumes and the Johnson and Dawson families will each receive a copy.

Financial donations in memory of the two victims have been directed to mental health organisation beyondblue and The Katrina Dawson Foundation.