Trine Skei Grande, the leader of the Liberal Party, and Knut Arild Hareide, leader of the Christian Democrats, have both announced meetings of the most senior party officials for Wednesday afternoon, Norway's TV2 has reported.
At the same time, the Progress Party has called a meeting of its central executive committee.
Erna Solberg, the leader of the Conservative Party and Norway's incoming prime minister, is pushing to forge a four-party coalition, joining her party both to Progress on its right wing, and to the two smaller, more centrist parties to its left.
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But a two-party coalition joining Progress and the Conservatives may be easier to achieve, given the differences between Progress and the two smaller parties over issues such as immigration and oil drilling in the environmentally sensitive Lofoten Islands.