A moment of brilliance from first five-eighth Kelvin Smith, who put in a burst of acceleration to score a try, got them back in the game.
They narrowed the gap further when second-five John Jones scored out wide and Andrew Tauatevalu converted.
Poverty Bay slotted a penalty goal to take the lead with seven minutes to play and then closed out the game.
Cairns said it “absolutely hosed down” through the second half and Poverty Bay did well to get the job done in those conditions.
The first half didn’t go so well, though, after a four-hour drive to get to Whakarewarewa Park.
“We were still on the bus, largely, for the first half,” Cairns said.
Poverty Bay hooker Rikki Terekia scored the first try but Central Bay of Plenty wrested back control for the rest of the half.
Cairns said his loose-forward trio — Tamanui Hill, Nicolas Carrizo and Will Bolingford — went well and Terekia was strong up front.
In the backs, Tauatevalu, normally a fullback, filled in at centre after the late withdrawal of Matt Raleigh because of illness.
Cairns said Scott McKinley, who played fullback, was solid and Smith had “a pretty good day, all up”.
Poverty Bay’s next pre-season match is at home against Hawke’s Bay Saracens on Saturday.
