Neither woman was available when Wanganui last defeated Manawatu, 16 matches to 8, at the Manawatu Lawn Tennis Club 12 months ago.
However, Romero remained a key fixture and his withdrawal with injury seriously depletes the strength at the top end of the team for Sunday.
The six males and six females will play their Manawatu counterparts in singles, doubles and mixed doubles, where they must win at least 12 of the 24 matchups to retain the cup.
Wanganui development officer Gene Ridgway said they will look to their other New Zealand level representatives in Butters, Leela Beattie and veteran Karen Cranston to carry the load, along with Wellington-based coach Simon O'Leary.
"These players are mixed in with local talent Paris Butters, Tim McKenzie, Patrice Mathey, Brian Keen, Sean Edmonds, Tara Butters, Charlotte Gollan, and Rachel Cronin - creating a balanced side of youth, talent, and experience that will put up a good fight.
"This is going to be a massive fixture."
Beattie, Cranston, O'Leary and Kyle Butters all got the clean sweep by winning their three matches when Wanganui last met Manawatu.
Ridgway said the visitors are bringing a top quality team.
"The tennis is going to be fast, powerful and exciting with a close finish predicted."
-Play starts at the Wanganui Tennis Club at 9.30am on Sunday, supporters welcome.