Public support for Spanish Prime Minister Mariano Rajoy and his ruling People's Party (PP) has significantly fallen in the wake of a corruption scandal, according to an opinion poll.

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

The survey, revealed on Sunday, 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.

While Rajoy has adamantly denied receiving secret payments, the growing scandal has provoked anger of Spaniards who were already frustrated with the government's handling of a deep economic recession and high unemployment.

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

Support for the PSOE in the poll was at 23.5 percent, a slight change from the 23.3 percent last month.

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.

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.

Source: Agencies