"However, Mr James' travel on both occasions was for parliamentary business and was in connection with his job."
Read the letter here:
Mr Carter said he was "assured that there has been no misuse of parliamentary funds to meet the costs of Mr James' travel to Wellington.
Responding to Mr Simpson's claims that Mr O'Rourke had also been involved in placing a bogus testimonial for his classic car hire business on Trade Me, Mr Carter noted that was "outside my area of responsibility".
"In closing, without further substantial evidence to allegations that have been made, I can take this matter no further", Mr Carter said.
Mr Simpson this morning said he was "absolutely disgusted because it didn't pass the sniff test in the first place."
He confirmed he had laid a complaint with police over the bogus Trade Me testimonial placed by Mr James three months before Mr O'Rourke became an MP in 2011.
Mr O'Rourke has said he knew Mr James had placed the reference but, because it was done before he was an MP, he did not need to apologise to the public. "It's probably not proper but it's no big deal, I wouldn't have thought."
Mr O'Rourke last week said Mr Simpson's complaint was "just politically motivated nonsense."
While he initially told the Herald he and Mr James lived at separate addresses, Herald investigations revealed both addresses applied to the same property - Mr O'Rourke's home.