Mocca said the election could mark a "model shift with respect to the neo-liberal policies that preceded it".
Argentina once prided itself on having more in common with Europe than many of its troubled Latin American neighbours.
But drug use in slums, widespread poverty and growing insecurity are still major problems plaguing the nation's 40 million people.
A scattered opposition of neo-liberals, social democrats and dissidents from the governing Peronist Party are threatening the Kirchner grip on power as the economic crisis takes a toll on the presidency.
Nestor Kirchner led Argentina from 2003 to 2007, with high world prices for the country's exports leading the economy to nine per cent annual growth and boosting his popularity and that of his wife.
But as world commodity prices collapsed, so did the popularity of the Kirchners.
Economists, citing figures disputed by the government, say the country will this year sink into recession.
Nestor has defended the couple's hegemony and its bid for industrial revitalisation, led by the auto industry, even as the president last year angered investors by nationalising the private pension fund system - and the country's largest airline.
In early June, the president announced Argentina would extend a $70m loan to support a local affiliate of General Motors while its beleaguered parent company undergoes bankruptcy reorganisation.
Nestor recently warned sceptical voters of the risk of a return to the economic crisis of 2001, the worst in the country's history.
"It's a choice between a return to the past and the consolidation of a national project," he said.
The main battle in the South American country's mid-term elections is set to play out in the Buenos Aires province, where some 40 per cent of voters reside.