The race is on to get candidates selected in electorates for next year's general election.
In the South Island, National has so far selected candidates in seven seats.
Labour nominations for all electorates will close on Friday.
"Candidates are aching to be the official candidate," Labour communications officer Jenny Michie said.
"As soon as they are, they have more mana and can get on with it."
An extension would be made to Friday's deadline for Christchurch Central, after MP Tim Barnett last week decided not to stand, to give people enough time to consider their nomination, she said.
Selection meetings would be held first in sought-after seats such as Dunedin South and Christchurch Central, Michie said.
National is putting a big effort into winning the West Coast-Tasman and Waimakariri electorates next year.
In the last election in West Coast-Tasman and Waimakariri, National won the party vote but not the electorate vote, said the party's Canterbury-Westland chairman, Roger Bridge.
The party believed both seats were winnable for National, and recent party polling confirmed that.
Boundary changes had also helped, he said.
List MP Kate Wilkinson is National's confirmed candidate for Waimakariri.
Chris Auchinvole, who lives at Lake Brunner and has offices in Greymouth and Motueka, is National's West Coast-Tasman candidate, up against Labour minister Damien O'Connor.
National had a good opportunity to pick up party votes in Dunedin South because of unrest in David Benson-Pope's electorate, said the party's southern regional chairwoman, Kate Hazlett.
Confirmed electorate candidates:
Colin King, Kaikoura.
Nick Smith, Nelson.
Chris Auchinvole, West Coast-Tasman.
Kate Wilkinson, Waimakariri.
Jo Goodhew, Rangitata.
Gerry Brownlee, Ilam.
Bill English, Clutha-Southland.
To be confirmed:
Selwyn, this week.
Wigram, two nominations.
Christchurch East, nominations open.
Waitaki, nominations open.
Port Hills, nominations not yet open.
Christchurch Central, nominations not yet open.
Invercargill, nominations not yet open.
Dunedin North, nominations not yet open.
Dunedin South, nominations not yet open.
- The Press
Is it a good decision to lower the alcohol limit for driving?Related story: Alcohol limits to be lowered