The IEC says voting in certain areas of Gaborone North could go "a few hours" beyond the official poll closing of 7pm due to the high turnout in the area.
Gaborone North registered over 20,369 voters, historically the highest numbers ever for a Gaborone constituency.
The constituency has a population of 46, 434 people comprising six wards.
By 530pm, a Mmegi newscrew found scores of voters still waiting in the blistering sun at Phakalane Primary Polling Station, with dozens more arriving.
The presiding officer declined to speak to Mmegi on the numbers who had voted already, saying they were under instruction from IEC to direct enquiries to the returning officer. The returning officer was said to be out.
At Ledumang Primary Polling Station, were just over 1,700 voters are registered, one voter said she arrived at 6am and only voted at 5pm.
On social media, other voters took to expressing their frustration at the delays in the constituency.
It remains to be seen whether the final tally of votes in Gaborone North will exceed 16,000, the record high for any Gaborobe constituency.