Little said a referendum on the question of euthanasia could also be held at the same time, following discussions with ACT leader David Seymour, who has been driving the issue, and a willingness by New Zealand First to support Seymour's End of Life Choice Bill if it went to a referendum.
"It is possible that there would be a referendum on euthanasia as well," Little said.
He also flagged a possible referendum on changes to the MMP system of representation.
"It has been floating around that if we're going to do a bunch of referenda, why wouldn't we put this question about whether we want to make those final tweaks to MMP, reduce that 5 per cent threshold to 4 per cent, get rid of the one-seat coat-tailing provision."
But he said no decisions had been made on that yet.
In 2012 the Electoral Commission recommended reducing the party vote threshold for entry to Parliament from 5 per cent of the vote to 4, and also abolishing the coat-tailing provision which means parties who win an electorate seat can bring in other MPs, regardless of whether they meet the threshold.