Marr added: "We stood and watched for a short while to see if it would fall off."
After watching the "rather large rat" for a number of minutes, Marr continued to walk along the road before eventually turning back, only to be greeted with the same persistent pest on the power line.
"It ran right along the cable until it got to the pylon where it sat. It even started to clean itself there," she said.
"It was on the line at one point and it even started to wee. I thought oh my god, what am I seeing'. It was like someone on a tightrope. You'd think it'd just fall off."
Marr added: "I wondered how it wasn't getting electrocuted, but my husband reminded me it was insulated which is why you see birds sit on it I suppose."
Director of Hawke's Bay pest control company Mayfair Paul Foulkes said he had "never seen a rat running across a power line before".
"Normally, the only rat-related problems we deal with are in commercial properties, backs of shops, in restaurants or in residential areas," he said.
"You see rats in business districts, in backs of shops or on roofs – but never on a power line. This isn't a common occurrence as far as I am aware."
Marr added: "It is nothing like I have ever seen in my life time and I don't think many other people would have either. I don't know what happened to it in the end because I didn't want to stand there all day watching a rat."