Labour Party president Nigel Haworth has set campaigners the task of raising support to 40 per cent of the party vote between now and the September election.

That's about 10 points above what it's polling now, and would be enough to ensure a Labour/Greens alliance would have a majority in parliament without needing NZ First.

"Our task in the party is simple - we just have to turn out the party vote to ensure we are in government," he told about 500 delegates at Labour's election year congress yesterday.

"I don't use numbers like 30 or 35... 40 is what we want, 40 I like."

Labour leader Andrew Little told the conference the party was in "amazing" shape for the campaign ahead.

"This isn't going to be an easy fight," he warned them.

"It's going to be close. It's going to be tough.

"I've faced tough fights before - and this is one fight we simply have to win."

Mr Little clearly signalled housing will be the main issue in Labour's campaign.

The party believes that the shortage - Labour calls it a crisis - is the government's weakest point.

"National's had nine years to tackle the housing crisis... where they have failed, we will succeed," he told cheering delegates.

Labour already has policies to build 100,000 affordable homes in 10 years and ban foreigners from buying existing homes.

Yesterday he added another - ending the tax break that allows people with multiple properties to use losses as a writ-off against other income.