An American man is looking for answers after coming home to find a stranger had entered his house and cleaned it.

Nate Roman, from the US state of Massachusetts, returned home from work on May 15 to find his back door open and his house smelling of cleaning products.

There were no signs of a forced entry and a quick check revealed nothing had been stolen.

But as he walked around the house, he found his bathrooms had been scrubbed clean and his bedrooms were tidy.

"They made the beds, vacuumed the rugs, scrubbed the toilets and left [toilet-paper] roses," he said in a post on Facebook.

The intruder did not leave a note, so Mr Roman said the whole experience felt "weird" and "creepy".

"No idea what to think about this," he said.

He called the police and changed his locks, but suspects a housekeeping service may have accidentally gone to the wrong address.

"It's possible that I forgot to lock the back door. They didn't break anything while entering," he said.

"I usually forget to arm my alarm during the day … so I don't have any video, despite having cameras."

'Waiting to open a cabinet and find that creepy artefact'

Mr Roman told the BBC he was braced to discover something out of the ordinary. ( BBC )

Speaking to the BBC, Mr Roman said the intrusion had left him shaken.

"It was a tense couple of days, just worried … because someone was in the house," he said

"It's like I've been waiting to open a cabinet and find that creepy artefact."

But if it does turn out to be just a case of mistaken address, he said he would be glad.

"I will say the bathrooms were very well done. My son's room has never looked better," he said.

"The one thing they didn't do was clean the kitchen, which was a little disappointing."