The GCC states - Bahrain, Kuwait, Oman, Qatar, UAE and Saudi Arabia - have a joint population of around 46 million, the majority of whom are foreigners.
In 2003, they launched a symbolic customs union which has been beset with problems, failing to meet its target date of 2005, with the transition period systematically extended.
And a monetary union announced in 2009 with the aim of creating a common currency has also failed to materialise, with just four nations (Bahrain, Kuwait, Qatar and Saudi Arabia) signing up to it.
The two-day Manama summit, set to begin on Monday afternoon, will also discuss other regional issues including the more than 21-month conflict in Syria, relations with Shiite Iran and the situation in Yemen, sources said.