When i first started thinking about getting to Australia or New Zealand ecologically i.e. not by plane, i started off thinking about a ship. I figured it would be the simplest way, and would do away with needing vaccinations and visas for every single country en route. However, i discovered that there are no fast ships to Australia anymore. Cruisers cruise, and cargo vessels crawl and stop often. You're looking at about a month to Australia from the UK. So for the average holiday it is out of the question, though GAP years are another matter. The fast passenger ship does not exist. Personally i think it's time they brought it back. Think about it, a ship that doesn't stop all day every other day, has fast engines and not too much excess weight (i.e. no shopping mall inside it, just, perhaps a cinema and and a few other things to keep people entertained) should be able to make the trip pretty fast. Why spent up to 72 hours on planes and transfers and overnight stays being miserable when you could relax on board ship for a week? It could catch on. Unfortunately, however, i discovered that they don't exist.
I started by searching for cruise liners going all the way. Such cruises are surprisingly hard to find.
I did find a useful article written in answer to a similar question: http://travel.timesonline.co.uk/article/0,,18409-2295291,00.html
If you don't want to read it the links it gives are as follows -
Strand Travel (020 7766 8220) organise trips on cargo vessels: http://www.strandtravel.co.uk/strand_voyages/index.aspx - via the Panama Canal, from £3,290pp, including cabin and all meals or via the Suez Canal from £2,785pp. See the article or the website for more information.
Andrew Weir Shipping (020 7575 6000) again, passage on working ships inc. ships that sail to and from the UK and New Zealand: http://www.aws.co.uk/cruises/ - I've given a slightly more direct link, since despite what is says in the article about the R. M. S. St. Helena mail ship, as far as i can make out, it doesn't go anywhere near Oz. (If you like the idea of going to one of the most remote islands on earth, go to: http://www.rms-st-helena.com/
As far as cruise ships go, there is a world cruise in January 2008 by Fred Olsen Cruise Lines (01473 742424) that will go to Sydney but it is already fully booked: http://www.fredolsencruises.com/fredolsen/index.jsp?fp=true - You can try going on the waiting list. It costs from £5,379pp to Sydney, including a flight back to London - which seems to undermine my whole idea, anyway! But better than nothing.
Similarly, P&O Cruises (0845 3555333) do world cruises, also usually fully booked, but again there is a waiting list: http://www.pocruises.com/pocruising/Home.aspx
And if you happen to be starting from Honolulu, Celebrity Cruises (0845 456 1510) go from Honolulu to Auckland, departing in November 2007, from £1,799pp: www.pocruises.co.uk
So basically, cargo ships are easier to get on, since they go all the time, but i believe they are generally slower. They cost less per night, but i think they can end up costing more than a cruise ship because they take longer to get where they're going. Having said that, the prices quoted in the article don't actually back this up. Cruises only go occassionally, and are usually fully booked.
Cargo ships - For an online site all about travelling on cargo ships see: http://www.freighter-travel-review.com/
Best of all, the site has a page listing passenger carrying cargo ship companies: http://www.freighter-travel-review.com/links.html - see this page for a lot of info.
The most obvious way would be to take the Trans Siberian Express all the way to Beijing (cheapest tickets are, i believe, for a straight, 7 day trip). Then, obviously, trains and ferries to Australia or NZ.
For a lot of information about the Trans-Siberian part of the trip, see: http://www.seat61.com/Trans-Siberian.htm
Here is a forum entry regarding getting from Beijing to Australia: http://forum.virtualtourist.com/discussion-317852-1-1-Travel-0-0-China-discussion.html
The people posting aren't giving links, but the gist is Beijing to Singapore can be done by train (almost, there is a bus ride in Cambodia) The advice given is to purchase a ticket from a local travel agent a few days in advance. For a lot of information abot this, see seat 61, starting at the China page: http://www.seat61.com/China.htm
Or what sounds more fun, the Eastern & Oriental Express luxury train runs the Bangkok - Singapore part of the route: http://www.orient-express.com [N.B. This costs a LOT of money!]
There is then a freighter from Singapore. The full route is:
Singapore - Noumea - Lautoka - Suva - Auckland - New Plymouth - Wellington - Timaru - Tauranga - Hong Kong - Ho Chi Minh - Jakarta - Sri Racha - Singapore
It is bookable as either a complete round trip 5,160 Euros per person (6,000 Euros single occupation) or as one of two segments:
Singapore - Auckland: 1,810 Euros (2,100 single)
Tauranga - Singapore: 2,589 Euros (3,000 single)
If you can't afford this, you can fly from Singapore.
Suggestions from the forum duscussion are: Tigarairways, which i assume is at: http://www.tigerairways.com/home/ - or Northair which i think is actually Air North at: http://www.airnorth.com.au/ but many major airlines fly from Singapore.
I can't find any sea transport direct from Beijing to Australia, unfortunately. So to do it by land it's apparently trains or buses all the way down to Thailand/Indonesia/West Timur then a problem as there may not be regular ferries. (And a potential problem crossing the West Timur border was mentioned). So basically, practically speaking, the ecological trip may end at Beijing or Singapore for the more organised/less adventurous. For info on how to minimise the ecological damage done by your flight, see the Ecoflying: What and How? page.