* Opposition Socialists ask PM Rajoy to step down
* Corruption scandal hits support for conservative Rajoy
* Opinion polls show no clear majority for either party (Recasts with comments from opposition Socialist leader)
By Tracy Rucinski
MADRID, Feb 3 (Reuters) - Spain's opposition Socialist Party called for the resignation of Prime Minister Mariano Rajoy over a corruption scandal on Sunday as a poll showed the lowest support on record for his centre-right People's Party (PP).
Media reports over the past two weeks alleged at least a dozen senior PP officials, including Rajoy, received payments from a slush fund operated by its former treasurer.
Rajoy denies wrongdoing, but the scandal has provoked fury among Spaniards already disenchanted by deep recession and high unemployment, as support for the two biggest parties slumps.
"Rather than the solution for this country, Rajoy has become yet another problem," Socialist leader Alfredo Perez Rubalcaba, who served as deputy PM under the Socialist government which lost a landslide election in 2011, told a news conference.
An opinion poll published in the country's biggest-selling newspaper El Pais on Sunday showed neither of the two big parties could win a clear majority in an election.
The Metroscopia poll showed 23.9 percent support for the PP - the lowest on record and down from 29.8 percent in the same survey last month. The PSOE was little changed at 23.5 percent.
Spain has suffered five years of recession or economic stagnation and unemployment - already the highest in the European Union at 26 percent - continues to grow.
The United Left Party, on 15.3 percent in the poll, double its level of support at the last election in late 2011, has also urged Rajoy to resign. But the PP's parliamentary majority so far rules out any chance of a vote of no confidence.
The survey showed 77 percent disapproved of Rajoy as head of government, and 85 percent had little or no faith in him.
Eighty percent said PP leaders named by the media as alleged recipients of kickbacks should resign.
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. (Reporting By Tracy Rucinski; Editing by Jason Webb)