Malawi's Vice-President Joyce Banda is be sworn in shortly as president following the death of Bingu wa Mutharika, officials say.
She is to become southern Africa's first female head of state after taking the oath in parliament.
Mr Mutharika, 78, went into cardiac arrest on Thursday and sources said on Friday that he had died, although his death was not confirmed until Saturday.
The delay in announcing his death had prompted fears of a power struggle.
There had been speculation that the late president's inner circle was trying to circumvent Malawi's constitution to prevent Ms Banda from taking over and instead install his brother, Foreign Minister Peter Mutharika.
However, the information ministry's director of information Isaac Ziba said: "This afternoon the information that I have from my seniors is the right honourable Joyce Banda, the vice-president of the republic, is going to be sworn in as president and head of state of the Malawi nation."
Ms Banda had fallen out with Mr Mutharika in 2010 and became one of his fiercest critics. She was expelled from the ruling Democratic People's Party (DPP) and formed the People's Party.
On Friday, Information Minister Patricia Kaliati had said Ms Banda could not take over as head of state because she had gone into opposition.
The UK, the US and the EU have called on Malawi to respect the constitution.
Appeal for calm
Since the government officially confirmed Mr Mutharika's death on Saturday morning, Ms Banda has insisted the constitution would be followed in the matter of succession.
"What is going on is that the constitution says when there is a vacancy in the office of the president, the vice-president shall assume office and finish the term," she told the BBC on Saturday.
"When that happens, the vice-president assumes office. We are now, today, going through the process."
She said she had met the heads of the army and police, the attorney general and other officials before giving a news conference on the situation.
Those officials were behind her as she spoke, saying a cabinet meeting would be held soon to discuss funeral arrangements.
She also said preparations were being made to bring Mr Mutharika's body back from South Africa, where he was taken after his cardiac arrest.
"In the meantime, I call upon all Malawians to remain calm and to keep the peace during this time of bereavement."
She said that 10 days of national mourning would be held.
Mr Mutharika governed Malawi for eight years, but was recently accused of mismanaging the economy and becoming increasingly autocratic.
He fell out last year with former colonial ruler Britain, which withdrew its direct aid, accusing the Malawian government of mishandling the economy and of failing to uphold human rights.
Malawi is one of the poorest countries in the world, with an estimated 75% of the population living on less than $1 (60p) a day.
The country has suffered shortages of fuel and foreign currency since the UK and other donors cancelled aid.