MADRID: Public support for Spanish Prime Minister Mariano Rajoy and his ruling People's Party has fallen as they have been engulfed by a corruption scandal, an opinion poll showed on Sunday.

Media reports over the past fortnight have alleged that at least a dozen top party officials, including Rajoy, received kickbacks from a slush fund operated by its former treasurer.

While Rajoy has vehemently denied any wrongdoing, the growing scandal has provoked the fury of Spaniards who were already disenchanted with the government's handling of a deep economic recession and high unemployment.

The centre-right People's Party (PP) was swept to power with an absolute majority in late 2011 as voters rejected the policies of the former ruling Socialists (PSOE).

But if a general election were called now, Spain's two biggest parties would be neck-and-neck, neither with a clear majority, a Metroscopia opinion poll published in the country's leading newspaper El Pais suggested.

The survey showed 23.9 percent of the public voting for the PP - the lowest level since the 2011 election and down from 29.8 percent in the same poll last month. Support for the PSOE was at 23.5 percent, little changed from the 23.3 percent last month.

Seventy-seven percent said they disapproved of Rajoy as the head of the government, while 85 percent had little or no faith in him.

Eighty percent of those polled said the PP leaders named by the media as alleged recipients of kickbacks should resign.

However, Socialist opposition leader Alfredo Perez Rubalcaba has failed to capitalise on the scandal threatening the credibility of his political rivals. The poll showed 89 percent mistrusted Rubalcaba.

Almost all respondents - 96 percent - said corruption was widespread and not adequately punished, according to the survey which was carried out between Jan. 30 and Feb. 1 and interviewed 1,000 people across Spain.