concrete slabs, do you need council approval?

it's in the title. I know I can build a small garden shed up to a certain size without requiring approval, but what if I want to put said shed on a concrete slab say 8 by 7 metres (or there abouts)?

I live in NSW on the central coast

The slab would be at the back of the block which has rear lane access and would eventually house a larger garage (which would require approval), but in the interim, what would I need to do?

and later, what would I need to do to use an existing slab to build a garage on?

My place has no sewer, water or anything under the ground at the back of the place, all that sort of stuff comes from the front of the property.

I say you would
I called my local council in Sydney and enquired about a 4 x 5m stab that would go under a decking......they said i needed to do a DA or go through certification. Boo hoo I said.

I did figure as much, thanks

I think if you already move in, you don't need to report council...unless it's really huge shed and concrete....or your neighbour reports you, which sometimes happen....