Biometric voter verification kits have failed to work in a number of polling stations visited by the BBC in Uganda.
Electoral Commission’s spokesperson, Paul Bukenya, said they had received reports that some of the kits had malfunctioned.
The electronic devices are used to capture and verify details of voters before they can be issued with ballot papers.
Long queues were spotted in most polling stations visited by the BBC, although there were delays in delivery of voting materials at some stations.
Voting was expected to begin at 07:00 across the country.
In Nansana municipality, voting materials did not arrive until 10:00 local time (07:00GMT). Some voters had started getting impatient and hurled insults at electoral officials.
In Masaka city, south of the capital, Kampala, reports say that polling materials were delivered at around 07:30.
There is only ordinary police presence and no heavy military deployment so far in places the BBC visited,