The Electoral Commission says it would be possible for the Mana Party and the Internet Party to campaign together under an umbrella group and share the party vote.
Mana on Sunday raised the possibility that it could share a joint list with the yet-to-be-launched Internet Party of Kim Dotcom.
That would mean their respective members would run in electorates under their separate parties, but only the umbrella group would appear under the party vote section on voters' ballots.
That umbrella group could be either of the two parties, or another party set up to subsume the other two.
Chief electoral officer Robert Pedan said the Alliance Party operated that way for the 1996 and 1999 elections.
Dotcom deal mooted
The Mana Party says a merger with Kim Dotcom's Internet Party is not an option, but an arrangement involving a joint list and sharing the party vote could be.
Mana leader Hone Harawira says he met with Mr Dotcom in February and had what he says was a general political discussion.
Mana's secretary Gerard Hehir says a formal merger is not an option, but there may be scope for an arrangement where they campaign together under an umbrella party to take advantage of the combined party vote.
No firm decisions will be made until the Internet Party is formally launched, expected to be on Thursday.
Professor Andrew Geddis from the University of Otago says the arrangement is like a marriage of convenience and similar things have been done in the past. He pointed to the grouping of parties under the Alliance.
"The Alliance party was the name on the party on the ballot paper that people ticked, but underneath remained Mana, the Green party was originally in there, new Labour was in there, the Liberal party was in there. So, they remained individual parties in their own right."
Professor Geddis said it would be important for Hone Harawira to retain his seat.