Ms Dawber's home is just three blocks from Dunedin Hospital.
Sent by BreastScreen Otago Southland from its Dunedin Hospital site, dated February 18, the letter turned up on March 4, nine days after the mammogram appointment.
Because of a phone call from hospital staff, Ms Dawber, a former Otago Daily Times photographer, attended the February 24 appointment.
''I am somewhat at a loss to understand how a letter could take so long to reach me ... 14 days.''
She was grateful to hospital staff and had no complaint about the service.
But the mail delivery time was a real concern, especially given her proximity to the hospital.
She fears timeliness will slip further when mail delivery days are cut from six to three per week from July.
It made no sense to send letters to Christchurch for sorting, she said.
''This double-handling results in the system requiring long lead times for appointments.
''So long that in my case the appointment letter missed the mark by nine days.
''They need a mail system [with deliveries] within two or three days.''
BreastScreen Otago Southland, whose parent entity is the Christchurch-based BreastScreen South, uses New Zealand Post.
In contrast, the Southern District Health Board switched to DX Mail about a year ago.
Additionally, Ms Dawber's daughter missed a Dunedin Hospital paediatric appointment last month with a visiting Christchurch specialist.
She received that letter five days after its date, the same day the appointment was scheduled, with no prior warning.
BreastScreen South lead provider manager Joan Miles, of Christchurch, said the organisation would discuss the 14-day delivery time with New Zealand Post.
Ms Dawber's letter was sent from Dunedin, because it was a short notice appointment.
Regular appointment letters were sent from Christchurch, four weeks before appointments.
That would be lengthened to five weeks when New Zealand Post reduced its delivery days, Mrs Miles said.
New Zealand Post Christchurch Mail Centre leader Safka Gibbs said Ms Dawber should contact the customer service team to have the delay investigated.
''There are a number of reasons why a letter might be delayed.''
Letters sent within Dunedin went to Christchurch for sorting before returning.
''Testing shows we consistently meet our delivery targets and 95% of standard mail is delivered in two or three working days.
''The delivery changes are being carefully designed to ensure we continue to meet our delivery targets after July.''
Asked if health providers should consider switching to a service such as DX Mail because of NZ Post's apparent delivery issues, Ms Gibbs said: ''Absolutely not''.
Responding to the paediatric letter issue, Southern District Health Board patient services director Lexie O'Shea said appointment letters were usually accompanied by a phone call from the hospital, which had not happened in this case and that was being investigated.
DX Mail was sorted in Dunedin, rather than Christchurch, and was delivered in one to three days, she said.
