they can ask for cfs anytime.....SOM means more like the army and airforce can come in for more manpower
they can ask for Defence Force assistance at any time as well, no need to wait for a Declaration, depending on the extent of the request (a few people or a bit of equipment) the local militarty Commander can approve it, or for the big requests,( like 3 C5 Galaxies to transport a Strike Team to Vic in 2.5 hrs -
) it goes to Chief of the Defence Force.
All a formal Federal Declaration does is activate Federal Government support agencies and allow people to access emergency assistance funds through CentreLink, as well as put in place the Federal Disaster Support Networks which includes the Insurance associations and a whole range of other "peripheral" organisation
Victoria (or any State for that matter) can acivate its own SOE, which will make available similar services (Recovery Centres, Support Services, Emergency Grants as well as a few extra powers to the Police I think in crowd control- that one might be state dependent)