A UN Security Council resolution, S/2008/447, that would have imposed sanctions against Zimbabwe, has been vetoed by China and Russia. The vote was 9 For - 5 Against. Belgium, Burkina Faso, Costa Rica, Croatia, France, Italy, Panama, United Kingdom, United States voted for the resolution, while China, Libya, Russian Federation, South Africa, Viet Nam voted against, with Indonesia abstaining. China and Russia vetoed the resolution. A press release from the UN can be found here. It includes a copy of the draft resolution.
China issued a statement attempting to justify its veto. It said that "a sanctions resolution against Zimbabwe would not help...".
In April this year, a Chinese vessel carrying 3 million rounds of ammunition (for AK47 assault rifles, also supplied by China; and Russia), and rocket-propelled grenades was interrupted by South African dock workers, who were concerned about their intended use, just after Robert Mugabe lost the March election. {subsequent violence by the military, and others, against Mugabe's opponents would seem to justify their concerns}
The UN resolution would have, among other items, required an embargo on the supply of arms, and financial transactions. China 's significant arms trade with Zimbabwe/Mugabe would have to stop immediately, and payments due for past shipments would be effectively forfeited.
China's veto was much more about China's self-interest than any concern for processes aimed at ending the violence (& need for arms!). Russia vetoed to protect its growing trade with Zimbabwe, and to support its communist ally.
{See also the Human Rights Watch pages on Zimbabwe's abuses of its people.}
John