The conclusions, from Labour's long-term and reputable polling company UMR, were presented to media in a campaign briefing tonight ahead of the party's election-year congress in Wellington.
Healthcare featured as a concern in each election that Labour fought in Government, but didn't rate at all in 2011, 2014 or this year.
Labour leader Andrew Little's congress speech on Sunday is expected to centre on housing.
Labour General Secretary and campaign manager Andrew Kirton conducted the briefing.
He also showed that in about 50 party-vote polls conducted by UMR since the last election, all but 11 of them gave New Zealand First the balance of power - which is similar to most public opinion polls.
He said the party received 550,000 votes in 2014 and was aiming for 720,000 at this election and that campaign funding was 300 per cent higher than it was at the same time in 2014, and the average donation via email appeal was $33.
Asked why he was giving so much detail, he said: "There's a level of confidence in the campaign that we are wanting to run this time and a level of openness that says we are going to go out there and win on the policies and the message and this issues.
"We are not afraid to say we have got some good tools."
Kirton gave details about the number of phone calls and door knocks the party had conducted since January 1 this year - 50,032 phone calls and 16,036 door knocks as of yesterday - using party activists and networks of volunteers who were not necessarily party members.
That was up 79 per cent on the same activity measure as 2014.
Kirton said the party had also made 70,000 robocalls (automated phone calling).
Each approach was trying to identify voters leaning towards Labour and who would be worth contacting six to eight weeks out from the election on September 23.
He said the party would be making a much bigger deal around the start of advance voting - two weeks out from the election. They would be doing less of the banner waving and hoardings and more of the activity that identified potential Labour voters.
We just need to make sure that our messaging, our organisation and our unity is as co-ordinated as our data.
"I can sit in Labour HQ in Wellington and see every single electorate and how many calls and door knocks have been made and how many calls and door knocks an individual candidate has made," Kirton said.
One of the main messages was about Andrew Little and deputy Jacinda Ardern.
"Breaking into the outer atmosphere of voter awareness in terms of politics is pretty difficult with the limited bandwidth that political parties have."
But the more people heard about Andrew Little, as a father, a husband, a kayaker, a cancer survivor, and the owner of a dog called Harry, the more people liked him and it started to "humanise" some of Labour's policies.
"We'll be telling Andrew's story and Andrew and Jacinda's story right to 11.59 pm on election night."
Kirton and others in the campaign team spent the day briefing MPs and other candidates on "shoe leather politics" in which the Victoria Labor Party in Australia had led the way.