Clark is currently embroiled in negotiations to form a minority government that she said must be "stable and durable."
The makeup will depend on deals struck over key policy issues with several minor parties, a senior official close to the talks told The Associated Press on condition of anonymity.
Further meetings with minor parties are scheduled Thursday, the source said on the condition of anonymity.
Clark's Labour party holds 50 seats in the 121-member parliament following last month's election, compared with 48 seats for the main opposition National Party. Labour needs 61 seats to control the house.
The Progressive Party, with one seat, will become a coalition partner. Others involved in negotiations with Labour include the six-seat Green Party, the nationalist New Zealand First Party with seven seats, the Maori Party with four, and the three-seat United Future party, reports the AP. I.L.