A Buenos Aires mayoral candidate aligned with Argentina's top opposition presidential contender has won the first round of city elections.

With 92 percent of election places reporting late Sunday, Horacio Rodriguez Larreta had 45 percent of the vote. Less than 50 percent will mean a runoff in two weeks between Rodriguez and Martin Lousteau, who got 25 percent of the vote.

Larreta, from the Republican Proposal party, is Cabinet chief for Mauricio Macri, the out-going mayor of Buenos Aires who is the top opposition contender for the presidential contest in October.

The results show Macri's party continues to enjoy wide support in Argentina's largest city. Macri has been mayor since 2007.

Sunday's elections included governor and legislator spots in a handful of places across Argentina, including Cordoba.