SEVEN-TIME Hongkong champions Fiji, the fallen giants of sevens rugby, have been installed as 7-4 favourites to lift the inaugural Rugby World Cup Sevens, which kicks off at Murrayfield in Edinburgh today. Bookmakers William Hill have construed their defeat in the Hongkong Sevens final as a minor aberration, although they have not ignored Hongkong winners Western Samoa's emergence as a potent force by making them second favourites at 11-4. Australia and New Zealand, semi-finalists at Hongkong, are joint third favourites at 5-1, while home advantage has shortened Scotland's odds to 7-1 as fifth favourites. Hongkong join South Korea and Romania as 250-1 outsiders to win the Melrose Cup, only ahead of 300-1 Spain and Taiwan and 500-1 Latvia and the Netherlands. Hongkong Sevens quarter-finalists South Africa are 11-1 and England are 14-1. A key factor in whether Fiji will live up to their favourites tag is their outstanding fly-half Waisale Serevi, who in Hongkong proved beyond doubt that he is the best sevens player in the world. Serevi carried the burden of an injury-hit side to reach the final in Hongkong, but not even he could inspire them to a fourth consecutive victory. But Serevi, who has been the focus of publicity from the Scottish press, is confident that Fiji's recovery has been swift. ''It was almost good in a way that we lost in Hongkong,'' he said. ''It makes us even more determined to win the World Cup. ''A lot of people in Fiji were counting on us to win Hongkong. Now we must do our best to become the first world champions.'' Western Samoa are not too concerned with the tag as second favourites, captain Danny Kaleopa saying: ''We have set our minds on doing well in the World Cup and we are not thinking about anything else.'' Samoa's trump card is likely to be fierce centre Lolani Koko, who will probably make his last appearance for his country before embarking on studies to become a religious minister. Australia, joint third favourites with New Zealand at 5-1, are missing two key players from the side that came close to beating the Fijians in Hongkong. Tim Horan and Jason Little, widely regarded as the world's best centre pairing, opted to represent their province Queensland in the Super 10 tournament. Coach Bob Dwyer hopes Tongan centre Semi Taupeaafe and 1992 Hongkong Sevens representative John Flett can make up for them. The New Zealand All Blacks, disappointed at losing to Western Samoa in the Hongkong Sevens semi-finals, have dropped the injured Marc Ellis and recruited two proven sevens players in Peter Woods and Todd Blackadder. Woods, 25, was impressive for a New Zealand B team who competed at last month's Fiji Sevens. Blackadder, a 21-year-old farmer, was a member of the Canterbury team which won the New Zealand national sevens. Coach Peter Thorburn, who steered the Kiwis to their last victory in Hongkong in 1989, returns to the helm after a two-year absence and has placed more emphasis on brute force and speed over a long distance. New Zealand were last night deliberating whether to call up John Kirwan, who is playing in Italy, as a replacement for Eric Rush. Rush is troubled by groin strain and they have to decide by this morning (Hongkong time) whether to risk naming him in theirfinalised squad or calling on Kirwan. Pool A: Fiji, South Africa, Wales, Romania, Japan, Latvia. Pool B: New Zealand, France, Ireland, Korea, US, Netherlands. Pool C: Australia, Scotland, Argentina, Italy, Tonga, Taiwan. Pool D: England, Western Samoa, Canada, Namibia, Spain, Hongkong. April 16: Hongkong v England; Hongkong v Namibia. April 17: Hongkong v Western Samoa; Hongkong v Spain; Hongkong v Canada.