The unopened letter contained a Pak'n Save voucher, which Olga often gives out to struggling clients at Christmas.
"I felt a bit disappointed because this girl could have really done with the help at the time."
Olga won the Whanganui Volunteer of the Year award in 2014 and often gives gifts from her own pocket.
A spokesperson for New Zealand Post said that, while uncommon, postal delays could happen.
"A delay in delivery of this length of time is unusual and unfortunate.
"The most likely explanation is that the letter was delivered to the wrong address and the recipient did not return the item in a timely manner."
"Our postal team does its best to deliver to the correct address, but mistakes sometimes happen."
Despite the incident, Olga says New Zealand Post does a fantastic job.
"I had a bereavement last year and I got 58 letters delivered to me in one day. Without the posties, I never would have got those.
"I've been brought up with the posties. I don't go on the internet or anything like that. I'm a pen and pencil person.
"I hope they're never made redundant. In happiness and sadness the mail comes to you," she said.
