Fiji, who have won four of the last five tournaments in Hong Kong, opened their latest effort with a 36-nil thumping of Japan.
RNZ reports earlier on day one Samoa went down to Australia 22-19.
The Samoans will try and revive their tournament but it doesn't get any easier with a match against England who are fresh off a 56-0 drubbing of South Korea and currently lie second in the World Series standings.
Fiji play Wales and New Zealand on day two of the tournament.
Meanwhile in World Series qualifying competition, Papua New Guinea have started well, bagging two wins over Uruquay, (26-21) and Guyana, (31-5).
Tonga weren't so convincing, being comprehensively beaten 29-0 by Uganda before sneaking past Jamaica.
In the women's qualifying tournament Papua New Guinea lost to South Africa 29-7 in the quarterfinals.
Japan eventually overcame South Africa in the final to book their place in next year's Women's World Series.