MADRID — Spain’s acting prime minister opened a two-day parliamentary debate Tuesday in hopes of getting enough support to form a new government and ending an eight-month impasse, but expectations of a breakthrough are low.

Mariano Rajoy, 61, told fellow parliamentarians that Spain needed a government, not a third election, following two inconclusive elections since December.

“Spain needs a government urgently,” he said, noting that most voters had chosen his conservative Popular Party in the December and June elections and that there was no alternative government on the horizon.

He also warned that further delays could bring asunder the economic progress the country has made since emerging from recession in 2013.

Opposition party leaders will have their say Wednesday prior to the investiture vote, when Rajoy needs an absolute majority of support from lawmakers in the 350-seat chamber. He is currently six votes short, having secured the backing of just 170 deputies, including his own party’s 137 lawmakers.

Should he fail to garner a majority, Rajoy could still prevail in a second vote Friday when he only needs more votes in favor than against. That could happen if the opposition Socialists abstain from the vote rather than reject him outright as they and other parties have pledged to do.

The Socialists, with 85 seats, say they will not support a party they blame for Spain’s 20-percent unemployment rate, political corruption and recent severe cuts in national health care and public education.

If no government is in place within two months after Wednesday’s vote, Spain will have to hold a new election on Christmas Day, Dec. 25 – an unwelcome prospect among Spaniards.

Rajoy has been in office since 2011 and has been running a caretaker government since the December election.

The elections saw the rise of two new groups — the far-left Unidos Podemos alliance, which ended third, and the fourth-place business friendly Ciudadanos party — that effectively ended Spain’s traditional two-party political system of the Popular Party and the Socialists.