Gordon and Valma Johnson have lived in Regina Lane, directly behind the Caltex station in Thames Highway, since they retired to Oamaru in 2001.
The couple said more than a decade of no issues related to the operation of the service station changed when redevelopment at the site, owned by Oamaru-based McKeown Group, started in 2017 and was completed earlier this year.
Part of the redevelopment involved the construction of a driveway bordering the fence line of the Johnsons' property, which is accessed around the clock by heavy vehicles.
Mrs Johnson said some stock trucks that used the access way had spilled effluent, which had caused a ''dreadful'' stench and posed a health risk.
''It's putrid and we shouldn't have to put up with it here,'' she said.
The couple contacted the Waitaki District Council to discuss their concerns, but were directed to the Otago Regional Council.
They were asked to provide more information, such as vehicle registration numbers and the companies involved.
After the couple did so, Mrs Johnson said the regional council contacted her and said an officer would investigate the issue this week.
''They don't like it in a built-up town area,'' Mrs Johnson said.
Mr Johnson was also angry about damage caused to a stone block fence that separated his property from the service station.
After he signed an agreement for the redevelopment to go ahead, he allowed trucks to use his driveway so they could pour concrete for the access way.
He said that work had resulted in damage to the fence that he wanted repaired.
The fence had also been hit by trucks turning into the access way, he said.
Another stone block fence was erected at the rear of his property, which Mr Johnson said was done without his knowledge.
McKeown Group managing director Ken McKeown said he would be happy to discuss the issue and that the company would repair the fence if required.
Heavy trucks were discouraged from using the access way, as easier access was available at the company's site on State Highway 1 at Alma, south of Oamaru, he said.
He said the rear fence was built to extend an existing fence and enclose the service station area, to avoid vehicles encroaching on private land to which they had access in the past.
