The anti-government rally was joined by League's allies Brothers of Italy and Forza Italia.
Italy's main opposition parties came together in Rome on Saturday during an anti-government protest.
It's the second time in two months that the leaders of Italy's right - Matteo Salvini, Giorgia Meloni and Antonio Tajani - have held a joint rally against the government of Prime Minister Giuseppe Conte.
Thousands of seats were placed one metre apart from each other to avoid criticism that people weren't distancing due to the ongoing coronavirus pandemic.
The League's leader Matteo Salvini once again called for new elections, vowing to "rebuild" Italy, in a promise to relatives of the country's more than 30,000 coronavirus victims.
He criticised the government's handling of the coronavirus crisis, calling for urgent measures to support businesses.
His party is still leading in the polls, but the polling gap between the League and the left-wing government coalition formed by the Democratic Party (PD) and the Five Star Movement has progressively shrunk.
The League had lost around 7 per cent of its voters in the year that followed the Salvini-triggered government crisis which led to the formation of a new government from which the League was excluded.
Nevertheless, Salvini stressed that the right-wing alliance, formed by the League, Brothers of Italy and Forza Italia "is ready", whether a new election takes place "in a week or in six months".
He also called for justice reform, an ever-present topic in Italian politics which has come up more in recent months following allegations that Salvini's indictment - for which he will stand trial in October - and Silvio Berlusconi's 2013 conviction may have been politically motivated.
The fact that he was in Rome also prompted him to call on citizens to elect a new mayor, in 2021; somebody who, he said, would "liberate" the city, currently governed by Five Star's Virginia Raggi.
"This country's capital shouldn't [just] be remembered by tourists [as having] potholes, garbage, rats and neglect", he said.