“What I would like…is that they will be fair, inclusive and transparent and that all the parties involved can work in equal conditions,” said Deputy Prime Minister Soraya Saenz de Santamaria.

She said Madrid was “concerned” by a warning from the Organization of American States, a regional grouping, which recently questioned whether the elections in the former Spanish colony will be fair.

In October, Venezuela rejected a request from the OAS to send an observer mission to monitor the elections.

OAS secretary general Luis Almagro has warned that opposition parties are having trouble getting air time on the media ahead of the vote in the crisis-hit major oil producer.

For the first time in 16 years of “Bolivarian revolution” under late president Hugo Chavez and his successor Nicolas Maduro, polls show their rivals could now win a majority in Venezuela’s National Assembly.

But many analysts fear the government will refuse to recognise its defeat, and the country could be engulfed in violence.