|The elections pose the first real challenge to|
the ruling Colorado party [AFP]
Oviedo was freed from prison last year and cleared of a coup-plotting conviction, and has formalised his presidential nomination under an opposition party.
Considered a populist with support among Paraguay's poor Indian majority, Oviedo is the only contender on the primary ballot for the National Union of Ethical Citizens, an opposition party he found in 2000.
Oviedo says he was once the victim of political persecution.
Now he calls himself the solution to the country's endemic corruption and poverty that affects up to half of the country's six million people.
Source: Al Jazeera and agencies