Scramble for last Rio Sevens spot
Already, 15 teams have qualified for August's Games, including reigning World Sevens series champions Fiji and 10-time winners New Zealand.
France and the United States, teams that won Olympic gold when the XV-a-side game was part of the programme until 1924, have also qualified.
For 16 more teams there is one last chance to join the global showpiece, with the likes of Sri Lanka, Mexico and Germany the rank outsiders.
"We are here to do our nation and ourselves proud. We have one chance. The opposition will be tough, but we are ready," said Samoa captain Faalemiga Selesele.
Top seeds Samoa actually won the Paris Sevens tournament last month but that wasn't enough to qualify for the Olympics.
They have a tough draw with Zimbabwe, Tonga and Ireland in their group.
Second seeds Canada are hoping to emulate their women's team, which has qualified for the Games.
"We will be setting out to play the best sevens rugby we possibly can and hopefully end up where we want to be at the end of the weekend," said Canada captain John Moonlight.
Agence France-Presse
