The plot was an "attempted coup d'etat," according to Justice Minister Rockefeller Vincent, with officials saying several people, including a Supreme Court judge and a police general inspector, were arrested.
Prime Minister Joseph Jouthe told a news conference that 23 people had been detained with money, guns and ammunition.
“These people had contacted national palace security officials, high-ranking officers of the national palace whose mission was to arrest the president ... and also to facilitate the installation of a new president,” Jouthe said, speaking alongside the minister of justice and the chief of police.
Moise, speaking later at the Port-Au-Prince airport on his way to launch the annual carnival in the coastal town of Jacmel, said the plotters aimed to kill him.
“I thank my head of security at the palace. The goal of these people was to make an attempt on my life,” Moise said. “That plan was aborted.”
Moise then went on to say that he was "not a dictator,” and that his term in office "ends Feb. 7, 2022.”
Leading opposition figures, however, demand that Moise step down immediately, saying his five-year term ended on Sunday.
They dismissed claims that a coup had been attempted.
"You don't carry out a coup with two pistols and three or four rifles," lawyer Andre Michel told AFP.
He added that Moise's term had ended and therefore he could not claim that a coup had taken place against him
Moise is refusing to leave office, arguing that he was not in charge during the first year of his five-year term in office which was led by an interim government.
Meanwhile, earlier on Sunday, an anti-government protest was staged in Port-Au-Prince, with demonstrators clashing with police which responded using tear gas. There were also reports of protests in other towns.