Colombo, Sri Lanka (CNN) -- Contrary to earlier plans, Sri Lankan President Mahinda Rajapaksa will only swear in a new Prime Minister Wednesday, with the rest of his Cabinet ministers taking their oaths of office on Friday, a government spokesman said.
A hill country parliamentarian, D.M. Jayaratne, will be the new appointee.
Authorities did not offer an explanation for the change of plans.
Wednesday also saw the release of the official results of the country's April 8 parliamentary elections. The ruling United People's Freedom Alliance (UPFA) won a landslide victory, according to the results.
The results were delayed for nearly two weeks until malpractices prompted a re-poll in two areas.
The Department of Elections said the UPFA won 144 seats, just six seats short of a two-thirds majority in the 225-member Parliament.
Analysts say that the near two-thirds majority would give President Rajapaksa an opportunity to effect constitutional amendments.
The main opposition United National Front (UNF) garnered only 60 seats, leaving seven to the newly formed Democratic National Alliance (DNA).
The DNA is headed by former Army Commander, General Sarath Fonseka, who won a seat in the Colombo district.
He led troops in last year's military campaign that defeated Tamil Tiger rebels. He is now under detention and faces two different courts martial over an alleged conspiracy and fraudulent activity in military procurements.
The newly elected lawmakers will be sworn in when the new Parliament meets Thursday.
Secretary General of Parliament Dhammika Kitulgoda told reporters that Fonseka will be escorted to Parliament from Colombo's Navy Headquarters where he is being detained so he could take his oaths.
He said he had officially informed the Ministry of Defence of the retired General's election as a parliamentarian.
The landslide victory for UPFA comes just two months after its leader and Sri Lanka President, Mahinda Rajapaksa, won the January 26 presidential elections by a majority of 1.8 million votes over his rival, General Fonseka.
It was the worst defeat suffered by the opposition United National Front