Labour Party president Moira Coatsworth has told members at the party's Congress to get 2000 more Labour voters in each electorate if they want to win the election.

The Congress began at the Wellington Town Hall this morning with an address by Ms Coatsworth to 450 people before breaking for the first closed door session on the campaign.

Ms Coatsworth said Labour's polling was rising but it needed to turn out 2000 more votes in each electorate. Local members needed to run "sharp" campaigns to get that vote out.

"There is much to be done. Right now campaigning is our relentless focus. We can win."

She said Labour was determined to win back the Te Tai Tokerau seat in the byelection on June 25. Labour's candidate Kelvin Davis will stand against Mana leader Hone Harawira and a Maori Party candidate and as a sign of the effort Labour will put into the campaign,

Mr Davis, rather than a more senior Maori MP, was given the place of responding for the party during the powhiri which kicked the Congress off.

"We are serious about winning back the Maori seats and we have candidates with great mana and determination to lead our Maori seat campaigns," Ms Coatsworth said.

She said she would lead a review of the party organisation after the election, and sent a warning that Labour needed to find talented new candidates outside its main sectoral interest groups. Developing a long term fundraising programme to fund future campaigns was also a priority, although the party was living within its budget.

She also reminded members of the history of the party, saying it had rebuilt New Zealand after the Great Depression and those same valued remained relevant today as inequality grew.

Wellington Central MP and campaign spokesman Grant Robertson opened the Congress with an amusing introduction, noting that the week was marked by two major events, the Budget and the Comedy Festival. He said Finance minister Bill English had prepared a show called Fiddler on the Hoof which he mistakenly delivered in Parliament instead of in the Festival.

He said other Festival skits included Gerry Brownlee's I fought the pie and the pie won, Peter Dunne's Hair Today, Gone Tomorrow and foreign minister Murray McCully's South Pacific "brought to you by the Royal New Zealand Air Force" - a reference to Mr McCully's use of the Air Force to fly to Vanuatu rather than take commercial flights.