"It is not right that we have China as a customer," it wrote in a statement released on Wednesday morning. "We have no mission as described in Stanghelle's article."
Aftenposten's political editor on Tuesday night wrote an article titled "On a smear mission for the Chinese?" in which he referred to "unconfirmed rumours" that First House had been hired by Chinese interests.
The firm said it did not normally comment on its customer relationships, but had felt forced to by the gravity of the accusations, which, if true, would amount to the firm breaking its own and its industry's code of ethics.
"It is unthinkable that we would participate in a debate in the public sphere as part of a paid assignment, unless it was stated who was the principal," it said in its statement.
In addition, by publishing what it itself described as "unconfirmed rumours", the statement suggested that Aftenposten was breaking the media's Code of Ethics, as First House had not been given the right to reply in the article.
Stanghelle on Wednesday told The Local that he did not believe his article broke any ethical code.
"If this was be in a normal news article, definitely, but this is not a news article, it's my opinion, and it’s clearly stated that it’s my opinion. So I don’t think I have a problem with the press code in Norway at all."
He argued that in his article he had not suggested that the Chinese government had hired First House, or even claimed to have any knowledge of who the group was working for.
"There are different theories as to what kind of interests it is. Is it business interests? Is it on the Chinese side or the Norwegian side?" he said.
"There are businessmen who really want to change him as leader of the committee, because the Chinese have more or less openly stated that it would be helpful for them if the people who voted for Liu Xiaobo were changed."
Per Højby, First House's Managing Director told The Local that the firm was considering taking Aftenposten to the official media complaints committee over the article.
“We are discussing whether we should take Aftenposten to the media's ethical committee. We have a six month period to actually conclude on question, so we are not in a hurry."
He refined the statement given on Wednesday morning, to include businessmen, either Chinese or Norwegian, working in China's interests.
“We have no assignments, paid or non-paid, for anyone related to China or Chinese interests," he said. "We have no assignments for clients interested in influencing the process of nominating the new Nobel Committee.”
He admitted however that some First House customers may have economic interests in China, but denied that this had prompted Wetland's article.
"We are the leading public affairs company in Norway, so it’s obvious that some of our clients could have economical interests in China, however this is not what this case is about. It’s a case about whether we have assignments as described in Mr Stanghelle’s article. We have no such assignments."
He said that Wetland had a long interest in the question of Obama's Nobel prize, and had not been prompted to write the article by anyone else. He also disputed Stanghelle's assertion that Wetland had broken some kind of ambassadorial code.
"It’s a common rule that When you are finished as an ambassador, you are not forbidden to talk about things like that, so long as you don’t break any rules as regard what's classified," he said. "His motivation for writing he article, which he wrote as a private person, is that he has had an interest in these questions for years."