In 2008, National's Allan Peachey had a 17,020 majority. Mr Peachey died almost a fortnight ago. There may be a tiny opening for Mr Boscawen, as new National candidate Simon O'Connor does not have as high a profile.
Mr Boscawen - who came to nationwide prominence during the 2009 Mt Albert byelection when he continued speaking after an activist placed a lamington on his head - said being an electorate MP would not drag him away from his family, because much of his work would be in Tamaki, where some of them live.
He would also be freer to spend time in the electorate because he would not have ministerial duties; he was formerly the Consumer Affairs and Associate Commerce Minister.
Dr Brash said he would support Mr Boscawen being re-elected, even if it meant denying himself a seat in Parliament.
"It would be fantastic. I'd be delighted if he won Tamaki. He would be absolutely upset, I suspect, because he doesn't want to win Tamaki."
If Act won about 1.5 per cent of the party vote and John Banks won Epsom and Mr Boscawen won Tamaki, Dr Brash - who's first on the party list - would be left out.
"I would certainly be disappointed not to be in there [Parliament]," he said. "But when you contest an election, sometimes you have to accept that you won't win."