Victoria
If you are on a road with a single continuous line down the middle, you must: stay to the left of the lines drive as close to the left side of the road as you can.
If you are on a road with 2 continuous lines (double lines) down the middle, you must: stay to the left of the lines at all times drive as close to the left side of the road as you can.
Queensland
You can cross a single continuous centre line to enter or leave a road, including entering or leaving a property, and to safely pass cyclists. You cannot cross a single continuous centre line to overtake or do a U-turn.
You must not cross a double continuous centre line except to safely pass a cyclist.
South Australia
You must keep to the left of single continuous lines. You must not cross these lines to overtake or make a U-turn but you may cross them to: enter or leave the road, enter a turning lane that begins immediately after the island, park in angle parking on the opposite side of the road, to leave enough room to safely overtake a bicycle rider
You must keep to the left of double lines and must not cross these lines, unless you have to avoid an obstruction or, if safe to do so, to allow enough room to safely overtake a bicycle rider.
West Australia
If the centre/dividing lines are continuous, do not cross that line unless you are turning right (i.e. to leaving or entering the road) or making a U-turn. The same applies if there is a continuous line on the left of a broken or dotted centre line.
Northern Terriroty
Unless a sign tells you otherwise, you can cross any type of dividing line when turning right at an intersection.
Tasmania
You can cross a single broken line only when it’s safe.
You can cross the double unbroken line to avoid a hazard or bike rider when it is safe.