There is no problem with the TV standard used on aussie DVDs - it's identical to ours, (ie. PAL).
Australia ARE however in a different region to us. They are 4, we are 2.
The majority (but not all) Aussie DVDs have a dual (or more) region code meaning that they will play OK on unmodified Region 2 equipment. However, there ARE occasional titles that ARE single coded for R4 - in which case a multiregion player is needed.
The EzyDVD website quotes region codes from the disc packaging. In many cases, this does not tell the true story - they often quote R4 (only) when, in fact the disc includes R2.
A reliable source of accurate region information is the Australian review/comparison website....
If you have an R2 only player - check your intended purchase out here before buying. Or, get your player modified. The savings that can be made by buying in Oz will quickly cover the cost of a region free mod, if you need one.