COPE initially contemplated calling itself the South African National Congress but abandoned that name after it emerged the ANC would object to a name similar to its own.
It then announced that its name was the South African Democratic Congress, but was forced to go back to the drawing board after it discovered that a party with a similar name had already been registered with the Independent Electoral Commission (IEC).
Friday's decision by the Pretoria high court came just two days before COPE supporters were due to meet in Bloemfontein to choose a leader and set out the party's policies and strategy for general elections, which are expected in March 2009.
"The people of South Africa are beginning to see ... a new beginning, a new agenda, a new hope for the country"
Mbhazima Shilowa, former provincial premier and one of COPE's founders
Keith Gottschalk, a political analyst at the University of the Western Cape, said: "The ruling clears the last obstacle before Bloemfontein and allows them [COPE] to generate publicity and hype for the conference."
The ANC had asked the court to prevent the new party from using its current name, as the Congress of the People also refers to a 1955 political summit that laid the foundations of the anti-apartheid movement and the current constitution.
The ANC was among the groups that attended the meeting.
"The ANC does not believe that this name should be appropriated for the exclusive use of any political party, particularly one that had no involvement in that historic event," it said in a statement.
The new party has not yet formally endorsed a programme, but it has hinted strongly it will adopt centrist, pro-business policies similar to those pursued by Mbeki during his nine years in office.
Investors praised Mbeki's government for refusing to abandon the fiscal restraint that many economists credit for nearly a decade of growth in Africa's richest
The business community, traditionally supportive of the ANC, fears that trade unions and the South African Communist Party (SACP) have too much influence in the ANC.
Zuma won strong support from the left when he beat Mbeki for the party's leadership in 2007.
While vowing not to make dramatic changes to policy, Zuma could face growing pressure from his allies in the Cosatu [Confederation of South African Trade Unions] and SACP to do so, especially if the ANC's pro-business wing defects en masse to COPE.
Mbeki has neither condemned nor supported the party.
In its first electoral test, COPE won more than a third of 27 contested by-elections this week in the Western Cape.
But the province is not a good gauge of the ANC's national support as the party has never won an outright majority there.
COPE's leaders are also hoping to capitalise on widespread unease over a corruption case that has dogged Zuma since he was fired as Mbeki's deputy president in 2005.
A judge dismissed charges against Zuma in September and said there had been high-level political meddling in the case, a decision that spurred the ANC to force Mbeki from office.
Prosecutors are appealing against the ruling.