My sister has to buy dairy free for one of her kids. You can get some at target/big w i think. They are more common now days as alot more people seem to have allergies. You would be after vegan easter eggs, there are a few online shops that sell them if you google vegan easter eggs or chocolate.

I just spoke to my sister (she rang while posting lol) and she said Darell Lea and coles have a range called Sweet Williams chocolate which is dairy free and most dark chocolate is dairy free although the kids probably wont like it anyway