One of the most trusted advisers of presidential hopeful Alberto Fernández on Sunday warned Fernández's candidate for the governorship of Buenos Aires province, Axel Kicillof, was "an ignorant".
His comments prompted an immediate rebuke from Fernández, who told Radio con Vos Kicillof was "far from ignorant".
"I would never say that Kicillof is an ignorant or that he's a Marxist. This is a fight among economists, an academic one. It's not my problem", Fernández insisted.
In an interview published Sunday, Nielsen told Perfil CEO Jorge Fontevecchia that fellow economist Kicillof, tied to the La Cámpora youth movement led by lawmaker Máximo Kirchner, was "a Marxist disguised as a Keynesian".
Initially refusing to answer questions that compared him to other economists inside Argentina's political arena, Nielsen eventually recognised Kicillof as a "Marxist" while clarifying that he, despite being a liberal, "had had very good Marxists professors".
"Kicillof is a Marxist. Kicillof is a Marxist disguised as a Keynesian", he eventually claimed.
Nielsen described Roberto Lavagna, who will contest Mauricio Macri for the presidency alongside Alberto Fernández, as "a Peronist and a social-democrat".
A trusted adviser to Fernández, Nielsen also recently expressed the need for the next government to reform Argentina's labour system, a proposal Fernández on Sunday rejected.
"In a paralysed country like ours, everything comes with a huge cost. Everything costs money because we're not selling. We have to get the economy starting again and not think about any labour reform", he charged.