New Labour leader David Cunliffe received less than a third of the support of caucus when the votes were counted yesterday.
But the support between himself and main rival Grant Robertson was more even if second preferences were counted.
The results show that Mr Cunliffe won the support of just 11 of the 34 MPs, Mr Robertson 16 MPs and Shane Jones 7 MPs.
If Mr Jones' supporters' second preference votes had been used, Mr Cunliffe would have picked up five more caucus votes to make a total of 16, and Mr Robertson would have picked up two, to make a total of 18.
All those voting had to rank the three candidates in their preferred order.
The second preference results were declared yesterday but were not actually counted.
If no candidate had reached 50 per cent on the first count, then the last placed candidate, Shane Jones, would have been eliminated and his supporters' second preference votes allocated to Mr Cunliffe and Mr Robertson.
But Mr Cunliffe won on the first count.He won the majority of party membership with 60.14 per cent and overwhelmingly the share of affiliated union support, at 70.77 per cent.
When the votes of the three sections - caucus, party and unions - were converted to their respective share of the vote, 40 per cent, 40 per cent and 20 per cent, respectively, Mr Cunliffe crossed the line at 50.15 per cent without needing to eliminate Mr Jones and count preferential votes. Mr Robertson won 32.97 per cent of the total vote and Mr Jones won 15.88 per cent.