An AFP correspondent saw few early voters at a polling station in Al-Qadsia, just south of the capital Kuwait City.
It was the first time that an election had been called during the Muslim holy month of Ramadan when the observant fast during the day.
Daytime temperatures were forecast to hit 45 degrees Celsius (113 Fahrenheit) in a further disincentive to turnout.
Polls were due to close at 8 pm (1700 GMT).
On the eve of the election, the emirate's sixth in the past seven years, the opposition urged voters to stay away, saying that taking part would legitimise corruption.
The law was ruled legal in June by the constitutional court, even though it dissolved parliament on other grounds and ordered today's election.
But its judgement failed to satisfy the opposition.
