Police and the Paihia Fire Brigade, which has a specialist line rescue crew, responded.
The brigade called ahead to another neighbour, who had a paddleboard, then secured it with a rope and used it to ferry the stranded swimmers to the river bank.
A member of the public and a female police officer took the board out, rescuing the girls first. The rescuers were able to stand up but the current was powerful.
Veronica, 13, who didn't want her last name used, was grateful to the police, firefighters and neighbours who had rescued them. They spent about 30 minutes on the island.
Her mother, Ge, from Watea, said she had no problem paddling out to the girls at first, but then the current changed and she was unable to return.
The 12-year-old was visiting from Hamilton.
Paihia Fire Brigade senior station officer Michael Fayne said the current would have been daunting so they did the right thing by waiting to be rescued.
He was not sure if an inflatable duck was a suitable buoyancy aid in such a strong current but everything worked out well in the end.
A Police Ten-7 crew, who happened to be in Kerikeri at the time, filmed the action for a future episode.