Oil production from the Organisation of the Petroleum Exporting Countries (OPEC) was 31.28 million barrels per day (b/d) in June.
New figures revealed production last month increased by 170,000 b/d compared to May.
It stated this is the fourth consecutive monthly rise since February as Saudi Arabia and Iraq are generating more oil,, according to Platts.
Saudi Arabia increased its output to produce an average of 10.35 million b/d in June.
Iraq produced more than three million b/d in the same period.
Margaret McQuaile, Senior Correspondent for Platts said: “This is the highest monthly level since August 2012 when the survey estimated output at 31.54 million b/d. At that point, output was on the way down. Now, output seems to be on the way up and at a time when the market could be looking at a lot more oil from Iran.”