The series resumes on Saturday after an extended seven week break over the Christmas and New Year period.
Fiji are not taking recent form for granted as they attempt to defend their Hamilton title.
They defeated reigning series champions South Africa and current leaders the United States en-route to the Cape Town title last year, to climb to third in the overall standings.
Despite winning the inaugural Hamilton event last year, coach Gareth Baber says Fiji have no right to be complacent.
"I'm not going to put any extra pressure on defending a championship," Baber said.
"I will just focus on getting them where they need to be to be able to perform at the (required) level and that starts with our first game on day one," he said.
"You stay as humble as you can to appreciate that any team can beat anybody in this tournament. I'm very very aware of that and we'll be making sure that we get our game right and put that into practice."
Fiji face Australia, Argentina and Wales in pool play.
Meanwhile, three Samoan players have recovered from injury in time for the Hamilton leg.
Samoa are 10th in the World Series standings after two rounds.
Coach Sir Gordon Tietjens said Alamanda Motuga, Tomasi Alosio were back from ankle injuries while David Afamasaga was over a hamstring strain.
"Three key players that were under an injury cloud but they've bounced back and they're here in Hamilton now," he said.
"I'm looking for big things because those three have certainly been great performers."
Samoa's strength is their speed and Sir Gordon said they had been concentrating on improving support for the ball carrier.
Tonga, on the other hand, are returning to the World Series on Saturday for the first time in five years.
Having qualified for the New Zealand and Australian legs of the series, coach Tevita Tu'ifua said they'd use the tournaments down under as preparation for their bid to qualify for a full berth in the next series at this year's Hong Kong qualifier.
But while his players are untested at this level, Tu'ifua said he expected them to perform.
"It will be huge for the group, for their development building up for Hong Kong which is our main priority target for this year," he said.
"However, it's a high performance level and we're expecting everyone to perform."
Tonga have been drawn in a difficult pool in Hamilton with series leaders the United States, England and Samoa.