Whanganui District Health Board loses $35 million each year to other health boards says corporate manager Brian Walden.
At this month's health board meeting, Mr Walden said Whanganui was charged by other DHBs when Whanganui residents received treatment from them.
"There's about a $35 million flow into other district health boards - as our patients go out to other care, the money follows them."
"So when the patients go down to Capital Coast or to Starship Hospital we are funding those places, and often those costs are quite considerable."
He said the costs are not balanced by payments from outside DHBs for patients coming in to Whanganui from other areas.
"Its about $35 million out and about $7 million coming in."
He said some of this loss was unavoidable due to patients having to travel outside the region for specialised care.
But hospital chief executive Julie Patterson said an unknown portion of the costs came from "out-of-towners" putting down a Whanganui address when they checked into the hospital.
"When you get people who comes to stay with you and they come from,say, Auckland ... if they get sick and they have to use our services, make sure they give their Auckland address, because we get the money from Auckland for them.
"If they give your home address, we pay for them."
Mrs Patterson said while this was a situation that applied all year around, the influx of people visiting Whanganui for the events such as the Masters Games did increase the chances that out-of-town people would need local health services.
"It goes without saying that out-of-towners will receive the same excellent service we strive to provide to our locals," she said.