Mana Party leader Hone Harawira says a decision on a potential alliance with the Internet Party has to be made before the end of June.
The parties are edging closer to an arrangement, with another meeting planned for Friday.
Mr Harawira said on Thursday had hoped to have it over and done with a week ago but some technical details still need to be worked out.
He said the Internet Party's leader could make a big difference. "That's something we've asked them to get really clear on because I don't want to be going in with Don Brash or Michael Laws or Rodney Hide."
Mr Harawira said he understands the party is close to selecting a leader.