Rising demand for oil abruptly reversed course in July and is set to proceed more slowly for the rest of the year due to the spread of the Covid-19 Delta variant, the International Energy Agency has said.

"Growth for the second half of 2021 has been downgraded more sharply, as new Covid-19 restrictions imposed in several major oil consuming countries, particularly in Asia, look set to reduce mobility and oil use," Reuters quotes the Paris-based IEA as saying.

"We now estimate that demand fell in July as the rapid spread of the Covid-19 Delta variant undermined deliveries in China, Indonesia and other parts of Asia," it said in its monthly oil report.

The IEA put the demand slump last month at 120,000 barrels per day and predicted growth would be half a million bpd lower in the second half of the year compared to its estimate last month, noting some changes were due to revisions in data.