Colombia's top electoral body said Tuesday it had launched an investigation into whether President Ivan Duque and his party violated campaign financing rules in the 2018 election that brought him to power.

In a statement, the National Electoral Council said the probe would determine if Duque and his Democratic Center party committed any "violation of electoral regulations on campaign financing," specifically related to a suspected $300,000 donation from a Venezuelan magnate.

The case is based on wiretaps conducted by the public prosecutor that unveiled conversations about the alleged donations from the businessman, Oswaldo Cisneros.

Involved in those calls were the head of the Democratic Center, Nubia Martinez; a former ally of ex-president Alvaro Uribe; and a suspected drug trafficker murdered in Brazil last year.

Foreign funding of political campaigns is illegal in Colombia.

Amongst those called to give evidence is fugitive former senator Aida Merlano, who staged a spectacular escape in October, giving guards the slip during a dental appointment.

Colombian President Ivan Duque (center) -- seen here celebrating his election victory in June 2018 alongside his family -- is now under investigation for alleged campaign finance violations Colombian President Ivan Duque (center) -- seen here celebrating his election victory in June 2018 alongside his family -- is now under investigation for alleged campaign finance violations Photo: AFP / RAUL ARBOLEDA

She is currently in Venezuela, whose President Nicolas Maduro is a fierce opponent of Duque.

The Democratic Center has denied receiving funding from Cisneros, but acknowledged accepting the equivalent of $185,000 from the CNE Oil & Gas company.

CNE is the Colombian subsidiary of the multinational Canacol Energy company, whose board of directors Cisneros sits on.

Duque took power after beating left-wing former guerrilla Gustavo Petro in a second round run-off.

"I don't believe in the investigative ability of an electoral body that is in the hands of the government," Petro said on Twitter.

Last week, Colombia's Supreme Court placed Uribe under house arrest over charges of fraud and witness tampering, in a separate case.