Hong Kong secured their place in the Asia/Pacific play-off with a 23-21 defeat of South Korea two weeks ago.
The winner of today's one-off match will become the 19th team to secure their place at RWC 2023, joining South Africa, Ireland, Scotland and Romania in Pool B.
Whoever loses on Saturday will have one remaining opportunity to claim a spot in France when they compete in the Final Qualification Tournament against Portugal, Kenya and the US in November.
Tonga warmed up for the play-off against Hong Kong by taking part in the Pacific Nations Cup 2022 in Fiji.