Foreign ministers from oil-rich Gulf states arrived in Beijing on Monday for a five-day visit as turmoil in neighbouring Kazakhstan raises concerns about China's energy security.

The officials from Saudi Arabia, Kuwait, Oman and Bahrain, as well as secretary general of the Gulf Cooperation Council (GCC) Nayef bin Falah al-Hajrah, will be in China until Friday, the foreign ministry has said.

Recent unrest in oil and gas-rich Kazakhstan has raised concerns in China, which has long invested heavily in its central Asian neighbour's energy industry.

The visit follows a flurry of diplomatic activity by China's foreign minister Wang Yi, including a tour of Africa as well as visits to the Maldives and Sri Lanka.

The foreign ministry did not provide further details on the Gulf ministers' visit, the first group trip of its kind, but they are expected to discuss strengthening energy ties with Beijing.

China has sought in recent years to bolster its ties with the Gulf states, with President Xi Jinping in 2014 aiming to more than double trade with the region by 2023.

State-owned newspaper Global Times said the visit may also "make breakthroughs" in talks over a China-GCC free-trade agreement.

The potential agreement was first tabled in 2004, with the two sides discussing in March last year the possibility of resuming negotiations.

Xi praised the Kazakhstan government's deadly crackdown on protesters as "highly responsible" in a message to leader Kassym-Jomart Tokayev last week.

He added that Beijing was willing to "provide support" if needed, state media reported.