A letter containing obscene language that was sent by Downer Group to Richmond residents was intercepted before many were able to read it. (File photo.)

It was a standard mailout to residents about a water shutdown, however the greeting was anything but.

A letter from Tasman District Council contractor Downer about a planned water shutdown began, "Dear C***" and was sent to a small number of properties in Lower Queen Street last week.

When visited by Stuff, some residents said they had not seen the offensive letter as it had been recovered before they checked their mailboxes.

But they knew about it because they had been visited by Downer and council staff to apologise to those who had already opened the letters.

READ MORE:

* NZ swearing on screen - we're getting more sensitive

* Downer may resume gravel extraction at Waimea West quarry

Those who weren't home were left an apology letter from Tasman District Council utilities manager Mike Schruer.

"Earlier this morning our contractor Downer delivered a letter to your property that contained inappropriate language," it read.

"The Tasman District Council had no direct input into the writing or distribution of the letters which was handled by Downer as part of its contract to deliver a council service.

"However, our logo was displayed on the letter."

In a joint statement from both organisations, Tasman District Council chief executive Janine Dowding said she was "horrified" at the language used in the letter.

MARTIN DE RUYTER/STUFF A Tasman District Council apology letter written to a resident in Lower Queen St, Richmond.

"I am extremely disappointed that some of our residents received this letter containing offensive language.

"We let Downer know that this is completely unacceptable, and they assured me that they shared our dismay and have taken action to make sure it doesn't happen again."

The apology letter said Downer management would conduct an internal investigation to find out how the obscenity occurred and would hold those responsible accountable.

Downer's general manager for water Gareth Mappledoram said the team were "appalled something like this could happen" and were taking it very seriously.

"A mistake like this is simply not acceptable and an investigation is currently under way. The local team have met personally with anyone impacted to apologise."

One resident who didn't see the letter, but was home when council staff came to apologise, said she thought the system must have been hacked into as a joke.

Another resident said it must have been very embarrassing for the council and she wondered if the language had anything to do with the fact residents had complained in the past about noise at the nearby Nelson Speedway.