The M5S announced that its members would vote on the proposed coalition with the PD in an online poll on Tuesday, between 7:00 am and 4:00 pm.
The two former foes have agreed to form a new governing coalition in order to prevent early elections that could catapult Matteo Salvini, the leader of the right-wing populist League party, to power.
The new government of the M5S and the PD is to be headed by outgoing prime minister, Giuseppe Conte.
Conte was also the prime minister in the troublesome coalition between the M5S and the League, which survived for only 14 months.
Salvini took down the government in August, seeking to cause snap elections and capitalise on his party’s growing popularity.
Conte on Sunday made clear his expectation that the talks for the ministerial seats in the new Cabinet would be finalised by Wednesday, and that the “political mood” between the two former opponents was good.
“It will be on Tuesday, Wednesday at the latest,” Conte said.
“Obviously I am confident on a positive outcome.”
Conte received the mandate to form a new Cabinet from Italian President Sergio Mattarella last Thursday.
If no agreement is sealed in the coming week, Mattarella is expected to dissolve the Italian parliament and set a date for a new general election.
