An Italian politician has called for apartheid on public transport in Milan.

A proposal to introduce racial segregation on trains, trams and buses in Milan provoked an outcry from Italian opposition politicians today.

The scheme was put forward by a representative of the anti-immigrant Northern League, the prime minister Silvio Berlusconi’s main ally in government. Matteo Salvini, the league’s secretary in Milan, told a rally to launch his party’s European election campaign that he wanted “seats or carriages reserved for the Milanese” on local public transport.

Dario Franceschini, leader of Italy’s biggest opposition group, the Democratic party, said: “One’s thoughts go back to the affair of Rosa Parks, the black woman who refused to give up her place on the bus and inspired Martin Luther King’s struggle.”

Salvini tried to downplay the row, insisting: “It was just a provocation to say the residents are now in a minority and, as such, need safeguarding.” But the Italian president, Giorgio Napolitano, spoke of a “worrying” increase in intolerance, while the opposition Italy of Principles party called on the government to disown the idea publicly.

However, Berlusconi, whose government is already under attack for its immigration policies after the Italian navy returned to Libya more than 200 boat people without letting them apply for asylum, said: “Salvini himself has said it was a quip, a provocation.”

The interior minister, Roberto Maroni, a Northern League member, hailed it as a “turning point” in his battle to stem the flow of immigrants through Italy’s Mediterranean islands. But the UN and human rights groups accused the government of violating international treaties to which Italy is a signatory.