China will send observers to Sudan when the south holds an independence referendum on 9 January, the Chinese Foreign Ministry said on Tuesday.
"At the invitation of both the north and the south, China will send observers to participate in the referendum," Foreign Ministry spokesman Hong Lei told reporters at a regular news conference.
"China is willing, together with the international community, to continue to play a proactive and constructive role for the sake of Sudan's peace and stability," Hong said.
South Sudan is scheduled to hold a referendum on Sunday, the outcome of a 2005 peace settlement that ended decades of civil war, to decide whether the major oil-producing region will take steps toward secession.
International observers worry that a mishandled referendum could risk destabilising the region.
"China hopes that the referendum in the south of Sudan can be implemented in a free, fair, transparent and peaceful manner and that all parties can put forth efforts in the interest of Sudan's peace and stability," Hong said.
Chinese companies are major investors in Sudan's oil, and China is Khartoum's top arms supplier, something long criticised by human rights activists and Western governments, especially because of the conflict in Darfur.
China, sensitive to criticism about its role in Sudan, has sent peacekeepers to Darfur and appointed its own special representative to the region to try and bring peace there.
The conflict in Darfur flared in 2003 when mostly non-Arab rebels took up arms against the government, accusing it of neglecting the region.
A series of cease-fires, negotiations and international campaigns has failed to end the fighting and law and order has collapsed in most of the region.