Agentina's President-Elect Javier Milei
Lawmaker and presidential candidate Javier Milei, speaks during a press conference in Buenos Aires AFP

Argentina's election campaign was marked by heated exchanges Wednesday as the incumbent president pressed charges against frontrunner candidate Javier Milei for dissing the national currency, which subsequently crashed.

President Alberto Fernandez announced he had reported Milei for "public intimidation" after the candidate said Monday the Argentine peso "isn't worth excrement."

Milei, who is presenting himself as an anti-establishment candidate, urged people away from investment in the local currency, saying: "never in pesos, never in pesos."

The currency crashed to over 1,000 to the dollar on the informal market, a record low, from 880 before the weekend.

The informal or "blue dollar" exchange rate is now almost three times the official rate of 365.50 to the dollar.

In his complaint, published by news agency Telam, Fernando invoked a section of the penal code that punishes acts that "inspire public fear or provoke tumult or disorder" by between two and six years in prison.

Fernandez also cited two other leaders of Milei's La Libertad Avanza (LLA) party, saying the trio's actions were directly responsible for the peso's collapse.

Milei retorted that the powers that be were seeking to "ban the most-voted political force" ahead of a first round of presidential elections on October 22.

He came out tops in a countrywide primary vote in August, and is ahead in opinion polls.

"Let them file all the complaints they want, nothing will prevent the beating we will give them at the polls," Milei said.

He said he had not even been in politics two years, and blaming him for the state of the economy -- with inflation at over 120 percent, poverty at 40 percent and a dearth of foreign currency -- was disingenuous.

Also Wednesday, the ruling party candidate and Economy Minister Sergio Massa, said he would request "a psychological and psychiatric evaluation of the candidates" before any second voting round.

"Being president requires a certain emotional stability," he said, without naming Milei.

The other presidential contender Patricia Bullrich has also expressed concern about Milei's "emotional instability."

Milei, an economist who is positioning himself as an outsider, has vowed to dollarize Argentina's economy.

He has also said he wants to abolish the Central Bank, ban abortion, liberalize the sale of arms and open up a market for the sale of human organs.

The dollar has long been a safe haven from the peso, and Argentines buy the currency whenever they can as a form of savings and protection from foreign exchange volatility.

The "blue dollar" has flourished in recent years as the government has restricted citizens to buying $200 a month due to diminishing foreign reserves.