David Seymour is closing in on National in two recent opinion polls.
A Curia poll conducted for the Taxpayers' Union, puts the Act Party on 14.9 per cent - while National's on 21.2 per cent.
Recent UMR polling data obtained by Newstalk ZB, also puts Act at 13 per cent.
The Act Party leader says told Mike Hosking it shows there's a growing appetite for a change in Government.
"At the election, Act plus National was 32 percent. In both of these polls, that block is up to 36 or 39."