United Future, or more precisely, its leader, Peter Dunne does.
United Future leader & one-man band, Peter Dunne, has brokered a deal with the National Party to support National in any post-election governance arrangement. Currently serving in the Labour government as Minister of Revenue, Dunne has rejected Labour - with effect after the election, of course.
Applying the Peter Principle - reworked by Mr Dunne as "What's good for Peter, is good for the party and nation" - he has negotiated himself a nice cabinet spot in any National government after the election.
Apparently after three years at the public trough collecting a minister's salary & perks it has dawned on Mr Dunne that Labour is no longer for him or United Future.
While arguing that a Labour-Green coalition allied with the Maori Party would pull government too far left of centre, Mr Dunne is no doubt more worried that such a multi-party coalition would squeeze him out of another run at the trough with the larger minority parties getting ahead in the queue for ministerial spots. And he has said as much, cloaked in the code of United Future having difficulty getting its policies addressed.
United Future is barely posting electoral support at 0.4 percent of the party vote; only Dunne's electorate seat keeps the party represented in parliament.
Even with 1 United Future seat on their side, National may still have a struggle to form a government without the Maori Party as latest polls show the gap between National and Labour coalitions narrowing.