National's improving fortunes in the polls have given a sense of urgency to an election meeting of the Council of Trade Unions.
President Ross Wilson said the closer race would add "a bit of spice" to the Wellington session.
The secretary of the Engineering Print and Manufacturing Union - affiliated
to both Labour and the CTU - Andrew Little, said the polls had "sharpened it up".
The CTU has already taken out radio advertising encouraging union members to get involved in the election and to be aware of the policies.
Mr Wilson said the ad attempted to counter the "spectre of the hard-nosed employer paying campaign contributions to the 'screw-the-worker' party.
He said the CTU also opposed across the board tax cuts - as promised by National.
Mr Wilson said the CTU did not tell members how to vote but it produced an assessment of work-related policies which gave Labour, the Greens and Progressives a tick and a National, New Zealand First, United Future and Act a cross.
"We're not doing this work to get a National Act Government elected, there's no question about that."
There was still a question mark over the Maori Party because while it had voted for the Employment Relations Amendment Bill it voted against paid parental leave.
Mr Wilson said the CTU supported an adjustment to the tax thresholds but opposed across-the-board tax cuts promised, but not yet detailed, by National.
"We don't think tax cuts are going to do anything than really return us to the policies of the 1990s.
We believe the money is better invested in public services, health, education and infrastructure."
The CTU's affiliates represent 300,000 union members.
The Public Service Association yesterday criticised National plans to cut public service "bureaucracy".
Economist and former adviser to Finance Minister Michael Cullen, Peter Harris, dismissed claims that the public sector had ballooned over the past few years.
The PSA, which maintains it is politically neutral, was last week accused by National of pushing Labour's agenda in an advertisement it placed in a newspaper.
Mr Harris, commissioned by the PSA to research the issue, said New Zealand's public service had gone from being slightly larger than the average public service equivalent in other Organisation for Economic Co-operation and Development countries in 1999, to significantly less by last year.
Labour was first elected to lead the Government in 1999.
Mr Harris said that on a national scale the public service made up only 2 per cent of taxpayers, and that cutting, for example, 10 per cent of it would bring minuscule savings with high social costs.
National finance spokesman John Key said Mr Harris had used selective data and that there was no weighting in the figures.
When adjusted for population or GDP, New Zealand did not have a small public sector relative to other Anglo-Saxon countries.
Mr Key also challenged Mr Harris' use of the gross Crown debt figures: 35.4 per cent of GDP in 1999 and 25.3 per cent now.
Mr Key said that in nominal terms, Labour had repaid only about $1 billion but the ratios had changed significantly because the economy had grown.
