BOGOTA Colombia's attorney general's office has launched an investigation into reports of the illegal financing of President Gustavo Petro's election campaign last year, it said in a statement on Friday.

The investigation is the latest twist in a political scandal that has destabilized Petro's government at a time when Colombia's first leftist president has tried to push a trio of bills for work, pension and health reforms through the country's Congress.

"(The investigation) will establish the possible authors of crimes relating to the financing of electoral campaigns from prohibited sources, violation of electoral finance limits and others that can be typified," the attorney general's office said in a statement.

Petro has denied any financing irregularities via Twitter. A spokesperson for the president was not immediately available to comment.

Petro accepted the resignations of both his former chief of staff Laura Sarabia and the former ambassador to Venezuela Armando Benedetti last week, after the attorney general's office said two former employees of Sarabia were victims of illegal phone taps after she reported the theft of $4,000 from her home.

Benedetti was accused of leaking information from one of the ex-employees to the press, which he has denied. Sarabia has also denied any wrongdoing.

A local magazine subsequently published audio messages that Benedetti allegedly sent to Sarabia, who worked for him when he was a congressman.

In one recording Benedetti uses phrasing that media outlets and politicians have interpreted as being related to campaign finance irregularities, though Benedetti said on Twitter the audio was "manipulated."

The National Electoral Council said in a statement it has called Benedetti and Sarabia to give evidence on the allegations on June 13.

(Reporting by Oliver Griffin; Editing by Alistair Bell)