Papua New Guinea's parliamentary speaker has refused to comply with a Supreme Court order reinstating independence leader Michael Somare as prime minister.

Speaker Jeffery Nape said Tuesday that he would only recognize the government of Peter O'Neill, who was elected by lawmakers in August while Mr. Somare was out of the country receiving medical treatment.

On Monday, Papua New Guinea's attorney general announced that the supreme court had ruled the election was unconstitutional, saying there was no vacancy in the prime minister's office at the time.

“The legitimate government of Sir Michael [Somare] as at the second of August has now been fully restored by the due process of law.”

The 75-year-old Mr. Somare was removed from office by a majority of lawmakers after spending five months in Singapore undergoing several heart surgeries. When he returned in September, Mr. Somare insisted he was still prime minister, saying his family had announced his resignation without his consent.

Mr. Somare is expected to be sworn in Tuesday amid heavy police presence in the capital, Port Moresby.

United Nations Secretary-General Ban Ki-moon expressed his concern Tuesday about the tensions in Papua New Guinea and called on all sides to exercise maximum restraint.

In a statement, Mr. Ban also expressed hope that the crisis will be resolved soon in a peaceful manner in accordance with the country's constitution.

Australian Foreign Minister Kevin Rudd on Tuesday called for calm, saying that “violence would help nobody.”

“The situation on the ground is calm….but this is still a tense situation and we are deeply concerned about it. We're monitoring it very closely and we are in contact with all the relevant authorities.”

Mr. Rudd told Australia's ABC Radio that political tensions are high because the country essentially has two “alternative prime ministers.”

Mr. Somare led Papua New Guinea to independence in 1975 and was serving his third term as prime minister when he took a medical leave of absence in December 2010.