Results released by the Zambian electoral commission showed that to date, Zata had 187,873 votes compared to the 96,325 votes by Vice-President Rupiah Banda, AllAfrica.com said.
The commission's Web site said with 47 of the total 150 constituencies reporting, Banda's Movement for Multi-Party Democracy was trailing Zata's Patriotic Front political party.
The reported tallies were 428,824 votes for the Patriotic Front and 228,764 for the country's ruling party, the Web site said.
Pregnant Mila Kunis wins 'Best Villain' at MTV Movie Awards
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend