The Sudanese Government and the region's many rebel movements "continue to pursue a military solution to the conflict" and they have made little progress in implementing the 2006 peace accord that was supposed to either end or reduce the fighting, Mr. Ban writes.
The mission itself - known as UNAMID - is increasingly the target of armed attacks and banditry, obstructing its ability to deploy rapidly and to fulfil its mandate to protect civilians and help implement the peace agreement.
"Reinforcements are slowly arriving, but the security situation and difficult environment in Darfur have delayed the arrival of equipment for incoming contingents," the Secretary-General states, noting that it is more than a year since the operation was authorized by the Security Council.
So far, just over 10,500 uniformed personnel, including troops, military observers and police officers, are in place across Darfur, far short of the estimated 26,000 blue helmets required when UNAMID reaches full deployment. More than 2,500 civilian staff have also been recruited, or 46 per cent of the total number of authorized posts.
Even bringing equipment and basic supplies into Darfur is exposing UNAMID staff to higher risk, given the volatility of conditions on the ground, the report points out.
Mission personnel "often undertake patrols and provide force protection escorts without adequate communication and transportation assets. UNAMID civilian personnel also work and live in an extremely unsafe environment."
A UN security assessment team which visited Darfur and the Sudanese capital, Khartoum, earlier this month is now finalizing recommendations to improve staff safety and security.
Mr. Ban says the effectiveness of the mission also depends on Sudanese Government cooperation on issues such as the freedom of movement of UNAMID staff, customs clearance, visas and the re-supply of the operation by air, rail and road.
He stresses that the Government has a responsibility to stop its aerial bombardments and military offensives and to "take concrete steps" towards disarming the so-called Janjaweed militiamen and other groups allied to Government forces.
"I call on the Government to comply with its obligations under international human rights and humanitarian law, in particular with regard to the protection of civilians," the Secretary-General says.
The report also calls on all rebel groups to commit to an immediate cessation of hostilities, start serious negotiations with the Government and fully cooperate with the peacekeeping mission.
"UNAMID, despite its broad mandate for the protection of civilians and assistance to peace implementation, is not designed to create a sustainable solution to the Darfur crisis. That is the responsibility of the parties to the conflict."
In addition, Mr. Ban reiterates that UN Member States need to provide the units and equipment still missing from UNAMID, including 24 helicopters and additional units dealing with logistics, heavy transport, medium transport and aerial reconnaissance.
The Security Council is expected to discuss Mr. Ban's report at a meeting next week when Under-Secretary-General Alain Le Roy, who has just completed a visit to Sudan, will brief the 15-member panel.
An estimated 300,000 people have been killed in Darfur since fighting erupted in 2003 between Government forces, allied militia and the rebels, while 2.7 million others have been forced from their homes and now live as refugees or as internally displaced persons (IDPs).