Outgoing Czech Prime Minister Andrej Babis on Thursday said he had formally submitted his resignation to the president following defeat in last month's elections.

Czech President Milos Zeman this week had already named Petr Fiala, the leader of the centre-right Together alliance, to form a new government.

"This morning our government has submitted its resignation," Babis said on Twitter.

The resignation is valid once it has been accepted by Zeman, who has remained in hospital with liver problems since October 10 -- the day after the vote.

Babis, a populist billionaire, will remain in a caretaker role until a new government is sworn in.

The Together alliance also this week sealed a coalition deal with a centrist two-party alliance.

This larger grouping holds 108 seats in the newly-elected 200-seat lower house of parliament.

The Czech Republic, an EU and NATO member with 10.7 million inhabitants, is grappling with a surge in Covid-19 infections and a sharp rise in energy prices.