Paula Bennett on the cusp of becoming Deputy Prime Minister

Paula Bennett, Minister of Local Government, Social Housing and State Services. Photo / Mark Mitchell.

Paula Bennett is on the cusp of becoming Deputy Prime Minister of New Zealand, but may have to lobby for a few more votes over the weekend to secure the job.

Based on publicly declared votes, Bennett has 23 National MPs on her side, though numbers are changing often. Simon Bridges trails behind, having secured the support of 10 MPs. A candidates needs 30 votes to become deputy to Prime Minister-in-waiting Bill English.

If no clear winner between her and Bridges is found by Monday - when a caucus vote will be held - it is understood both candidates will give speeches to the party before a private ballot takes place.

But first, the two ministers were making last-ditch telephone calls to undecided MPs. Bennett is mostly working alone, while Bridges has a lobbying team which is understood to include two MPs.

Bridges, the Transport Minister, is attending the wedding of National MP Simon O'Connor tomorrow. O'Connor is marrying Bridges' sister Rachel Trimble.

"Unfortunately, he hasn't invited lots of members of Parliament along," Bridges said. "So I don't get the opportunity to enjoy my sister's wedding and lobby at the same time."

Both candidates kept a high profile yesterday. Bridges opened a cycleway in Auckland, while Bennett, the Social Housing Minister, opened a new community housing block in Glen Eden.

Bennett fired a shot at Bridges, saying his side was trying to position himself as if "they've got the back bench," Newshub reported.

"That back bench can see I've got something to add as well", she said. She made a point of naming some of the junior MPs who were backing her.

Bridges has positioned himself as the champion of the back benches. One of the key concerns raised during the leadership contest this week was that the power was too concentrated at the top of the National Party. Bridges said National "needed to evolve" beyond the John Key Government.

Out of the public declarations so far, there is a rough pattern of younger MPs voting for Bridges and more senior MPs voting for Bennett.

Bennett has secured the most support from ministers, including Justice Minister Amy Adams, Foreign Minister Murray McCully, who is a close friend, and Auckland Central MP Nikki Kaye.

Her supporters are pointing to her Auckland base, the male and female balance and her good relationship with English.

Bridges' backers are painting him as a way to bring in a new political generation. Trade Minister Todd McClay has also pointed to the Auckland-raised Bridges' provincial representation in the Tauranga seat.

Bridges points out he is originally from West Auckland and understands New Zealand.

"I'm originally a westie, I also have a very good sense of provincial New Zealand so there's a lot of things that I think I bring to this that are relevant to New Zealanders today."

Some caucus members were divided about who they would support.

Auckland Central MP Nikki Kaye said: "I have been a bit torn because I rate them both very highly. But on balance I'm voting for Paula because I think she's a very strong leader for Auckland and will be a very complementary person for Bill.

"But I do think Simon has got a huge, huge future and it has been a hard decision."