If you are shipping things in boxes or carton style, shipping by sea is definitely not recommended.
Check out freight forwarding. It's a cheap commercial method of using excess cargo space in commercial planes to fly things by air form one country to another. I've moved countries many times and what I've done is arrange the freight fowarders to pick up my stuff a week before I fly and when I touch down at my destination a week later, all my stuff is there at the airport already.
The catch is that you have to pick our cargo up from the airport itself or alternatively arrange for a courier (could be expensive) to pick them up and send them to your new place. Or you can ask a friend or rent a van or something.
jetta.com.au was the company I used but there are many such companies out there. In 2006, I shipped about 15 carton boxes or stuff (including transformers) at a weight of about 250kgs total for about $450. In SG, I paid another $70 for a courier to send these to my apartment (this is not the expensive type courier but the commercial type which the freight forwarder or the airport would be able to recommend).
If you have lots of things and by this I mean an entire apartment full, I recommend just renting a container. This is the type that goes on ships, unfortunately. A container can fit an apartment full of stuff, including all your furniture and it would cost in the region of $1500 to $2000 (not sure, usually company pays), but also depending on destination. Down side of this is time.
If you're shipping stuff to HK, I don't foresee it being more expensive than say shipping stuff to AU from other places because HK is along the main shipping routes.