The film only has a few scenes filmed in Hong Kong, but there is a good reason for that. When the anti-communist nature of the film's plot leaked out, there were protests by local Communist sympathisers (it was filmed only one year after the 1967 Communist riots) who hoisted effigies of both Peck and American President, Lyndon Johnson. As a result, the local HK Colonial Govt figured it was too hot a potato to handle and kicked out the film crew. The director, J. Lee Thompson, was able to snatch a few sneaky scenes though before leaving. The crew went on to film most of the Asian scenery in Taiwan (including some shots around Keelung docks) and the finale was actually filmed in Wales which stood in for rural China.
Anyway, as with all films that have some HK scenes, the stage is set by seeing the rather cliched (but never boring, for me at least) shot of a plane landing at the territory's former airport in Kowloon. We get a rather nice view of the area in Kowloon Tong where St George's school used to stand (I was told this is where the Australian International School stands now). It's the low rise building directly below the plane in the second shot. Also in the 2nd and 3rd shots are the former version of Osborn Barracks when it still consisted largely of Nissen huts.
Finally, a rather nice shot looking directly down the line of the famous runway, with the low rises of Kowloon City on the ground underneath.