The 37 new posts are in addition to the 20-member Cabinet of President Wickremesinghe, who took over in late July following Gotabaya Rajapaksa's exit.
It did not say where the former leader was headed but the Thai foreign ministry, as well as a source in Colombo, said Wednesday he was seeking a new safe haven in Thailand.
He said the text of the draft of the 22nd Amendment to the Constitution was changed after the ouster of former president Gotabaya Rajapaksa.
"Our campaign for a system change would continue, although we ended our campaign here at this site," Vidarshana Kannangara, another activist said.
Wickremesinghe further said that there is no point in blaming the former president for the economic crisis and urged all parties to come together to take the country out of the economic mess.
Rajapaksa arrived in Singapore on a private visit from the Maldives after fleeing his country. Rajapaksa has been issued a new visa, extending his stay here till August 11.
Prime Minister Narendra Modi has sent a congratulatory letter to Sri Lankan President Ranil Wickremesinghe after the latter got elected as the 8th President of the island nation.
In a statement released in response to media queries about Rajapaksa's visit to Singapore, the Immigration and Checkpoints Authority said that he was granted a short-term visit pass on arrival.
The 73-year-old six-time former prime minister secured 134 votes in the 225-member House while his nearest rival and dissident ruling party leader Dullas Alahapperuma got 82.
Wickremesinghe was sworn in as the acting president of Sri Lanka before Chief Justice Jayantha Jayasuriya.
Rajapaksa, his wife Ioma and their two bodyguards arrived in Singapore from the Maldives on board a Saudia airline flight.
Lankan President Rajapaksa, who is expected to honour his promise to resign on July 13, was looking at taking a Sri Lankan Air Force AN 32 or a commercial flight to land in India.
President Rajapaksa was not present in the presidential House when a mob stormed the building on Saturday. Sri Lanka's total foreign debt stands at USD 51 billion.