A single vote, allegedly cast in error, secured parliamentary approval for labor reforms in Spain on Thursday, unlocking billions of Euros in European Union aid.
The conservative People's Party (PP) is crying foul saying a "computer error" meant one of its members "voted no, but on the screen, the vote appeared as yes."
It was an "anomaly" and should be "rectified," PP party spokesperson Cuca Gamarra insisted.
The legislation narrowly passed in a 175-174 vote.
The vote was so close that House Speaker Meritxell Batet initially said the bill had been rejected, but she quickly corrected herself.
PP President, Pablo Casado, said the party will challenge the legislation in the Constitutional Court.
Labor reform a key promise by PM Sanchez
The narrowly-passed reform grants more power to labor unions in bargaining contracts and also lowers the number of Spanish workers on temporary contracts.
The landmark reform is a long-standing campaign promise of Spain's Socialist Prime Minister Pedro Sanchez.
"This is the most important law of the legislature," Labor Minister Yolanda Diaz told parliament before the vote.
She added the legislation would counter the country's chronic unemployment problem.
In November, the jobless rate was 14.1%, compared with the 19-country eurozone average of 7.2%.
Nine smaller parties joined the Socialist party and its junior coalition partner Unidas Podemos (United We Can) to vote in favor of the measure.
Its approval meets a condition for aid from the EU's €800 billion ($917 billion) coronavirus recovery fund.
Sanchez's government agreed with business and union organizations in December to push through the bill, but was unable to build a stable parliamentary majority until Thursday's vote.