Nationally, nearly 38,000 untreated patients were cut from elective surgery waiting lists in the year to June 2012.
National Health Board director Chai Chuah said there were a number of reasons patients were dropped from the lists, including cases where the risk associated with surgery had become too great or the patient opted to defer their treatment indefinitely.
Those with less serious or improving conditions could be sent back to their GPs. Some might have moved away from the area where they were due to have surgery, or chosen to seek treatment privately.
The figures show that, while more people exited the National Booking Reporting System (NBRS) at the WDHB last year, fewer had surgery.
Mr Chuah said the NBRS contained DHB-reported information regarding people on surgical waiting lists for elective treatment.
In August, a WDHB media release said the large volume of elective surgery work put through during the year to June 2012 was the most the DHB had ever delivered.
WDHB clinical director of surgery Mark Stegmann said the health board stood by that statement.
He said 310 of the 1135 untreated WDHB patients cut from waiting lists last year ended up being treated in an outpatient clinic or at another hospital.
Whanganui MP Chester Borrows also reiterated his praise for the local DHB, having earlier applauded its elective surgery result.
He said it was the sixth-best performing DHB in the country, in terms of the Ministry of Health's elective surgery target.
That benchmark aims to increase the volume of elective surgery discharges in New Zealand by at least 4000 each year.
Mr Borrows also noted the WDHB's work in reducing waiting times. From June 30, people who had been accepted for elective surgery or an assessment to determine their need for elective treatment were expected to be seen within six months.
The WDHB met that goal, having had 85 patients waiting more than six months for treatment a year earlier.
The Ministry of Health's target champion for elective surgery, Clare Perry, said: "We have set expectations for district health boards that they reach the goal of six months by June 2012, five months by June 2013 and four months by the end of 2014."
Mr Chuah said the Government had committed $904 million since 2008 to meeting the "improved access to elective surgery" target.