Italy’s deputy prime minister Matteo Salvini has told his party he wants to keep its fractious coalition government going, but is ready to see it collapse if he cannot push through his flat tax plans and other priority measures.

Two populist and stridently anti-European Union political groups, both fierce rivals, surged in Italy's parliamentary election at the expense of the country's traditional powers, but neither gained enough support to govern alone, preliminary results showed.

Italy's populist opposition 5-Star Movement says it is ready to run the country after voters triggered the demise of prime minister Matteo Renzi with a stinging defeat on his reforms referendum.