Labour's fund-raising is "way below par" leader Andrew Little has admitted.
He's denying the party faces a financial crisis and says it has money in the bank.
"But we've certainly had a couple of years of poor financial performance... our fund-raising activities are way below par and that's been the focus of attention for a few months," he told reporters.
"I'm confident we have the means in place to step it up."
Mr Little says Labour would be able to fight a by-election if Mt Roskill MP Phil Goff contests and wins the Auckland mayoralty next year.
"We can run good one-off fund-raising events for by-elections, we get a lot of troops on the ground," he said.
"But we do need to have a much more strategic and systematic way of doing our party-wide fund-raising and we're working on that."
Labour spent half as much as National on last year's election campaign, and was out-spent by the Greens for the first time.
Official figures showed it spent $1.27 million on election advertising, slightly less than the Green Party's $1.29m and half of National's $2.6m.