Iran was more sceptical of the idea and its oil minister Bijan Namdar Zanganeh said on leaving the meeting that the charter would have "no impact on OPEC and its mechanism or decision taking".
Also speaking late on Monday, Saudi Energy Minister Khalid al-Falih said the charter would allow OPEC and non-OPEC countries to establish "a structure for technical meetings, ministry meetings, regular summits" with the OPEC secretariat in Vienna acting as "the main coordinator".
While Monday's agreement in Vienna had intially sent oil prices surging, on Tuesday they were more subdued amid fresh worries over the global economic outlook.