Epsom MP John Banks says he will work to rebuild the ACT Party.
Mr Banks retained the seat for ACT by a comfortable majority in the election on Saturday, but will be the party's sole MP as it only gained 1.07% of the party vote.
Leader Don Brash has announced he is stepping down, saying he takes full responsibility for the party's poor performance.
Asked if he was keen to take up the role, John Banks told Morning Report's election special on Sunday he is not sure a party with just one MP needs a leader.
Mr Banks says he intends to work to rebuild ACT into one which espouses values, the free market and freedom of choice.
He says the media was wrong to write ACT and himself off, and his cup of tea with National Party leader John Key was a lifesaver.
The men's discussion was recorded without their knowledge at an Auckland cafe on 11 November and the subsequent controversy dominated the third week of the election campaign.
Mr Banks says he will have to set up another tea date with Mr Key to talk about a possible coalition deal. He says he believes National now has the numbers to achieve its goals.
National secured 48.06% of votes in Saturday's election, which will give the party 60 seats in Parliament. John Key says his party has the support of ACT, and United Future, which also won one seat.
Brash admits mistakes made
Don Brash took over the leadership in April this year after rolling Rodney Hide, but says he can't stay on as leader when he is not in Parliament and assumes Mr Banks will be the new head of the party.
"We made some mistakes. Some of them were personal mistakes of mine, some of them were mistakes made by other people but finally I have to take responsibility, that's why I've resigned."
Dr Brash says that negative news media coverage of the party played a major role in how it performed in the election.
He says will formally hand in his resignation on Sunday, but will continue working with ACT to help the party rebuild towards the 2014 and 2017 general elections.