Global oil supply, aided significantly by non-OPEC countries, is estimated to have increased to 91.85 million barrels per day, said an International Energy Agency (IEA) report.
According to an oil market study, strong growth in North America's oil production is expected to push up the total non-OPEC supply by an average of 1.4 million bpd year-on-year to reach 55.4 million bpd in the last quarter of 2013.
OPEC oil supply declined to 30.41 million bpd owing to supply disruptions in Libya and Iraq. The supply could not be pushed up despite a marginally higher output by Saudi Arabia.
Mounting unrest by oil workers in Libya led to a closure of oil fields and export terminals while Iraq output was constrained by pipeline damage in the north and bad weather in the south.
Oil production from Kuwait and Algeria too edged lower during June.
Marginally higher production by Saudi Arabia, Iran and Angola partially offset the reduced production from other OPEC countries
Saudi Arabia's crude oil edged up to 9.7 million bpd to become the highest level produced in the last seven months. The rise in production is due to increased domestic demand for crude during peak summer season.
Last year Saudi had increased production to an average of 9.8 million bpd from June to August in order to meet the domestic demand.
However increased natural gas supplies appear to be tempering demand for crude this year with the latest data indicating that crude used for direct burn averaged 380 kilobarrels per day in April this year as compared with 440 kbp in April 2012.
Preliminary data shows that oil production in the UAE and Qatar remained unchanged at 2.73 million bpd and 725 kpd respectively.
IEA trimmed the growth forecast for oil demand in 2014 by 100,000 barrels per day to 1.1 million bpd, due to weak economic growth.
However the growth in global oil demand for this year is expected to remain unchanged.