Mr Gilmore allegedly called the waiter a "dickhead'' when he refused him more wine and gave him his business card saying something like "Don't you know who I am? I'm an important politician'', The Press reported today.
It has also been suggested that Mr Gilmore told the waiter he would tell the Prime Minister's office about his behaviour and have him sacked.
Mr Riches this afternoon confirmed to the Herald he'd heard Mr Gilmore use words to that effect to the waiter.
Mr Riches said he was disappointed that Mr Gilmore had apologised for his group's behaviour when it was "absolutely'' his own behaviour that was in question.
"It's a shame because I thought this could just lie, he could apologise and that would be the end of it, but to sort of blame everyone else ...''.
He told the Herald that two of the four in Mr Gilmore's group had left by the time of the incident.
"It was because most of the group had already left, he was cut off service, he did the old, "do you know who I am, I'm an MP''.
"I thought it was just disgusting.''
Mr Gilmore initially denied the claims but this morning issued an apology via Twitter and a later press release saying: "As a group of diners our behaviour was at times boisterous, and I sincerely apologise for any offence this may have caused to staff and/or patrons''.
"I intend to convey my apologies on behalf of the group to hotel staff, and understand that Members of Parliament should uphold, and be seen to uphold, the highest of standards at all times.''
Mr Key said Mr Gilmore was well and truly aware that he didn't meet the high standard required of MPs, and for that reason he's apologised for any offence he may have caused.
"Mr Gilmore's apologised to the staff at the Heritage Hotel, he's also apologised to me. I accept that apology and we'll move on from here.''
Mr Gilmore said hotel staff had unfairly blamed him for the behaviour of the group he was with, and he denied using his position as a politician.
Mr Gilmore told The Press the group of five shared four bottles of wine over several hours, and he had had one beer before dinner.
"I can't be 100 per cent sure of everything I say after having a bottle and a half of wine, but I think someone has misinterpreted what was said.''
However, he was "not aware'' of being rude or making the alleged comments to the barman, he told the newspaper.
While "some inappropriate comments might seem to have been made'', they had been apologised for, he said.
Mr Riches told The Press he left the note for the waiter because he felt Gilmore had been "a bit rude'' and he felt "a bit embarrassed by what happened''.
Mr Gilmore, 39, was in Hanmer Springs attending a National Party regional conference, which was attended by Mr Key.
A spokeswoman for Mr Key said his office had received no complaints over the matter but would look into any that were received.
Hotel management declined to comment.
- additional reporting Newstalk ZB
