Judith Collins is asking National supporters to vote for David Seymour in Auckland's Epsom electorate.
Ms Collins echoed Bill English's message at the last election when making the request on the campaign trail today.
"I am very happy to say we want the party vote in Epsom, please, and in this particular electorate you can give the first tick for the electorate to David Seymour," she said.
"I would welcome him being part of a National/ACT Government."
Ms Collins was at pains to make sure it was seen as an appeal to voters rather than an edict.
"I am asking the people of Epsom rather than telling. It’s always important to be respectful of people and their votes."
National's leader also stated her admiration for ACT's leader is well known.
"Everyone knows I think David Seymour is an excellent local MP, so I don’t need to do anything else, have little cups of tea or anything, because everybody knows that David Seymour and I work very well together.
"A National Party Government is best served with ACT as its partner."
In the latest 1 NEWS Colmar Brunton poll ACT rose to 4.8 per cent support after reaching 3.1 per cent in June’s poll.
The latest poll results would see ACT boost its MP allocation from one to six, assuming it wins an electorate seat.