Sitting for the first time in the dock of accused, Fernandez faced charges of corruption. Now a senator with a significant following, she reportedly entered the courthouse while being shielded by crowds of supporters.

The trial, which could last as long as a year, will address multiple corruption allegations dating from Fernandez's two terms as president from 2007 to 2015.

These include accusations she received kickbacks from construction firms that got lucrative sweetheart deals on projects.

Hours before she appeared in court, Fernandez slammed the trial as a political "smokescreen" aimed at hurting her campaign for vice president this year.

Fernandez, who strongly denies all the allegations, fired retorts on Twitter at her accusers and rival President Mauricio Macri.

"Clearly it's not about justice," she tweeted.

"Just about creating a new smokescreen that aims to distract Argentines and Argentina - increasingly less successfully - from the dramatic situation our country and our people live."

The recession-hit South American nation is heading for presidential elections in October, with centre-right Macri coming under pressure from high inflation, a weak local peso and job losses.

Fernandez shocked the nation on Saturday by saying she would run for vice president alongside unrelated former cabinet chief Alberto Fernandez, a veteran political operator who has both backed and criticised her in the past.

In another tweet she said the trial was an "act of persecution" with the aim of putting an opposition candidate in the dock during an election campaign.

The charges against her could end in a sentence of up to 10 years in jail. As a sitting senator, she currently has immunity from arrest, however.

Australian Associated Press