A woman who posted a letter to an address just six kilometres from her home has arrived at its destination more than 20 years later.

New Zealand mother Jeanette Baker had just given birth to her daughter Tyler when she decided to send out thank you cards for the gifts she received after hosting a baby shower in February 1993.

After posting one of the handwritten letter from Wainuiomata to Waiwhetu - just a 12 minute drive via a delivery van - the card arrived late last month.

And in that time frame, her daughter, who is now 23 years old, has finished school, become a hairdresser and moved out of home.

Mother Jeanette Baker (far left) had just given birth to her daughter Tyler (right who is now 23 years old) when she posted a card to a friend in 1993 - the letter arrived last month

The handwritten letter was sent from Wainuiomata to Waiwhetu - just a 12 minute drive

'It blows me away. Where has it been? Where has it been sitting? Has it been tucked away somewhere?' Ms Baker told NZ Stuff.

But despite going missing for more than two decades on, the mystery remains around where the letter had been.

The snail mail began when the letter was addressed to the right street - Douglas Street in Waiwhetu - but the wrong property number was listed.

Ms Baker said she only found out about the delay when recipient Carolyn Ferguson, who still lives at the address, told her she had just received the card.

The letter Ms Baker sent in February 1993 - has arrived at its destination - 23 years later

'Isn't it incredible? I got such a shock. I thought, Oh my God, where did this come from?' Ms Ferguson said.

New Zealand Post said the stamps on the letter suggested it was previously processed through the postal network twice.

'We have to speculate that perhaps the letter was delivered to the wrong house, and sat there for many years before being put back into the mail network,' a spokeswoman said.