The Prime Minister's office in Papua New Guinea has advised that Sir Michael Somare has resumed office.
Sir Michael voluntarily stepped aside as Prime Minister in December to allow for investigations into charges of misconduct in office.
Sam Abal was named acting prime minister in his place.
But the media advisor to the Prime Minister's office, Betha Somare says Sir Michael has since received advice that he could not legally step aside, and he's now resumed his duties after taking five weeks leave.
"We issued a statement earlier that he had stepped aside but we've been advised by the lawyers that he could not step aside, he just took his leave."
Betha Somare says the Prime Minister will step down once the chief justice sets up a tribunal to consider Sir Michael's alleged failure to submit full income returns to the Ombudsman Commission, going back nearly 20 years.
She says Sam Abal is now deputy Prime Minister and is comfortable with Sir Michael's decision.
Meanwhile, Transparency International in Papua New Guinea says the government's disturbing pattern of adjourning parliament to suit undermines the country's constitution.
Parliament won't sit again until May following a brief session on Friday to elect the Governor-General.
During that sitting, the opposition tried to launch a motion of no confidence but was outnumbered and MPs now won't convene again until the tenth of May.
Transparency International chairman, Lawrence Stephens says this means legislation may then be rushed through and in the meantime things will be done by ministerial decree.
It appears that it's more convenient not to have people in parliament so they have less opportunity to raise votes of no confidence in the leadership. By not being there they can't vote and this appears to be a tactic being engaged which really undermines the whole basis on which the constitution was established.
Betha Somare, from the Prime Minister's office says even though parliament has adjourned Sir Michael will still have other prime ministerial and electoral duties to fulfill.