The survey by the Centre for Policy Dialogue, an independent research organisation, showed Banda and his Movement for Multi-Party Democracy party with 41 percent of the vote against 38 percent for Sata’s Patriotic Front.
Six percent of voters were undecided, and the rest were committed to smaller parties, the poll said.
Banda, who has presided over more than five years of strong economic growth in Africa’s biggest copper producer, was shown broadly in front in the countryside, and Sata in the capital, Lusaka, and the northern Copperbelt.
An alliance between Sata and another opposition party, the UPND, crumbled this year, improving the chances of a new full term for Banda, who moved into the presidency after the 2008 death of his predecessor, Levy Mwanawasa.
Sata, a gruff populist who has criticised Asian investment in the mining sector, gave Banda a very close run in the former British colony’s 2008 election.
Since independence in 1964, Zambian elections have tended to pass off peacefully, although the kwacha has weakened over the last month, in part because of the political uncertainty and elevated government spending.
Banda prides himself on his farming roots and is a former associate of Zambia’s first president, Kenneth Kaunda, whose reliance on Soviet-style central planning drove the economy into the ground in the 1980s.
He has since abandoned socialism in favour of free-market economics to the point that his administration is looking to launch a debut $500 million eurobond shortly after the election.