In terms of this year's election, "it is not a done deal", he said.
"I have not decided. I have not made up my mind because there are a whole lot of negatives. It's a big decision, I'm not committed either way."
It was "fair to say that a lot of people are talking to me to go back".
"A lot of them wanted me to go back with National."
Mr Mark said that he was "very, very comfortable" with his working relationship with National and the fact Health Minister Tony Ryall had appointed him to two district health boards was "a hell of compliment".
Asked about the attractiveness of returning to Parliament as Mr Peters' likely successor, he said: "There's ups and downs with all of that, too."
It had been a challenge to establish himself after he left Parliament because he believed ex-MPs were tarnished by their political history.
However, he was now lead Treaty negotiator for Ngati Kahungungu ki Wairarapa and was serving on two district health boards as well as being Carterton Mayor. He would not give up those roles lightly.
"Currently I work very well with the current Government and I have good relationships with Labour. To get this Treaty settlement through at the level I want I cannot afford to undermine those relationships and I'm doing this for my iwi."
Mr Peters was not available for comment last night.