National party leader Simon Bridges says his leadership is not under threat.
Mr Bridges has been criticised over his announcement of Botany MP Jami-Lee Ross's sick leave, when he said the issues in question were potentially "embarrassing".
He said he was clear that he had made mistakes.
"I regret a poor choice of words but I've learnt my lesson.
"I understand this is about personal health matters for Jami-Lee Ross and his privacy - I get that."
Mr Bridges says it could be February before Mr Ross is back at Parliament.
His sick leave was completely separate to the inquiry into the leaking of travel expenses, Mr Bridges said.
"I do not know who leaked them. Jami-Lee Ross has been very clear with me he didn't and I take him at his word."
The inquiry is likely to report back within the next two weeks, he said.
"I believe, I hope, that we'll have results this week, certainly in the next fortnight.
"And that will deal with that."
But he said he did not know whether that would mean the person who leaked the information would be identified.
"I haven't seen a report, formally or informally."
Mr Bridges said his leadership was not under threat, and he was very focused on what he was doing.
"I've got a great team, the best in politics, we are the most popularly supported party and we're out there focusing on the things Kiwis really care about at the moment."
Last week Mr Bridges said criticism from the New Zealand First leader that National was moribund and leaderless was a "vintage" Winston Peters tactic of distracting from the real issues facing New Zealand.