After two delays, organisers said 70,000 tickets would be available in the first phase, during which only three-day passes are being sold.
Disappointed racing enthusiasts called The Straits Times late Thursday to complain that they have been having problems getting into the F1 website for hours. Those who tried calling also could not get through.
Those who tried to buy over the counter also had some difficulties, with only three people able to purchase tickets at one of the post office ticket stations in three hours, according to the newspaper's website.
"I am trying to spend money but I can't, due to a computer problem," Mark Benterman, a British Airways pilot, was quoted as saying. "If Singapore GP cannot sell it online, then they shouldn't have offered the tickets on the internet."
The cheapest of the passes for the September 26-28 event are going for 168 Singapore dollars (119 US dollars). The most expensive are 1,388 Singapore dollars for seats at either the premier pit or along and after the start and finish.
Organizers pushed back public sales twice, from last December to last month and then to after the Chinese New Year.
A total of 85,000 spectators will be able to watch the event.