Shooter Maia Wilson and midcourter Claire Kersten have been called into the team as injury cover for the tournament which involves New Zealand, Jamaica, Fiji and Malawi.
Wilson, who has seven test caps, has been included in the side with shooters Ameliaranne Ekenasio and vice-captain Maria Folau, who are both to be managed through the four-day series which starts on Wednesday.
Kersten, who made her Silver Ferns debut last year, is a late inclusion as cover for wing defence Kayla Cullen, who has been ruled out with a knee injury.
Ekenasio, recalled into the national team after taking time away from the game to start a family, has a finger injury, while Folau continues her comeback from a niggling knee complaint.
Cullen will sit out the four-day series due to a knee injury, but is expected to make a full recovery in time for next month's Commonwealth Games.
Southby said the move to bring Wilson and Kersten into the side was precautionary.
"We've got a heavy workload over the coming weeks and while the Taini Jamison Trophy is an incredibly important part of our season, we are also looking at the bigger picture of a demanding Commonwealth Games campaign next month," she said.
"Maia has been in the environment before and we feel confident she can make a seamless transition back into the shooting circle, while Claire made her debut last year and also knows our systems well."
- Silver Ferns squad: Katrina Grant (captain), Maria Folau, Ameliaranne Ekenasio, Temalisi Fakahokotau, Shannon Francois, Kelly Jury, Grace Kara, Claire Kersten, Bailey Mes, Te Paea Selby-Rickit, Samantha Sinclair, Michaela Sokolich-Beatson, Maia Wilson.
