French voters planning to back centre-right incumbent President Nicolas Sarkozy in next month's election have sex less often than their left-wing rivals, according to a poll published Friday.

The survey, conducted by the respected polling institute Ifop on behalf of the pornographic magazine Hot Video, measured the intensity and variety of the sex lives of various voting blocs using several criteria.

According to the results, voters for Sarkozy's UMP make love on average 6.7 times a month, slightly less often than supporters of his main challenger, the Socialist Party's Francois Hollande, on 7.6.

Followers of Marine Le Pen's far-right anti-immigrant National Front top the frequency league, having sex eight times a month, while those of centrist Francois Bayrou manage only 5.9 trysts in the same period.

Right-wingers also report having had fewer partners over the course of their lives, with seven compared to nine on the left, but once again it was the extreme right on top, with Le Pen supporters claiming 10.

But these extra partners don't seem to satisfy the far-right, as 31 percent of them declare themselves unhappy with their sex life, compared to 26 percent in the population as a whole and 21 percent among Socialists.

Supporters of Jean-Luc Melenchon's Communist-backed Left Front were the most sexually frustrated, with 35 percent of them complaining.

Ifop said it had conducted the poll among 1,411 adults in a weighted sample designed to reflect French society, and had taken care to minimise the margin of error "inherent in a questionnaire dealing with such intimate topics."