getting there

You will most probably have to transit via Australia, eg Brisbane. For example, ThaiAir to Brisbane, then a local budget/charter airline to Nadi.

Unless times have changed (and improved) you're not going to find direct flights from SE Asia to Fiji.

I dare you to go by land:)

You can get flights regularly to Fiji from both Brisbane and Sydney. Air Pacific, or Pacific Blue.

There are no direct flights from Bangkok or Singapore but it is announced that commencing December 3rd, 2009, there will be two direct flights per week (Thu and Sat) between Hongkong and Nadi/Fiji on Air Pacific. Anything else would have to go through Australia or New Zealand.

The cheapest way will definitely be via Australia.
You can fly a budget airline like Air Asia, Tiger Airways or Jetstar to get there from SE Asia, then go on to Fiji with Virgin Blue. This routing is likely to work out much cheaper if you can make up your mind about the dates and book well in advance.

Be careful if arriving in Brisbane with Tiger - they fly into Gold Coast, not Brisbane. Not sure if they fly direct to Sydney either.

when i was on air pacific last month i think i read they were to soon introduce flights nonstop fiji to asia somewhere, so check the airpacific website i guess

Travel tip! Direct flights between Nadi and Hong Kong commence on 03 December 2009. To book flights via Australia prior to this date, please contact our call centre in Fiji on 679 672 0888 or in Hong Kong on 852 2737 6755, from the airpacific.com website, cheers, C.

Korean Air flies Bangkok-Inchon-Nadi for US $870 one-way. Try http://travexnet.com/airlines/thailand_international_flights.asp for fares from Bangkok, and Misa Travel for fares ex Singers.