Zanu-PF lost its majority in parliament for the first time last year to the Movement for Democratic Change (MDC), and Mugabe was forced to share power with his rival Morgan Tsvangirai, the MDC leader, who was appointed as prime minister.
"We have to restore our party as the people's choice, the only choice, the people's party," Mugabe said.
The Zanu-PF congress comes amid reports that Zanu-PF is facing a deep split over Mugabe's succession.
Mugabe, 85, took up the party leadership in the 1970s at the height of the guerrilla war against the white-minority government of Zimbabwe, then known as Rhodesia.
He has ruled Zimbabwe since its independence from Britain in 1980 and is hailed by his supporters as a liberation hero.
Mugabe has already been endorsed as the Zanu-PF candidate for the next elections slated for 2013, when he will be 89.
Washington Ali, a London-based founding member of the MDC, said what is happening in Zanu-PF is "very disappointing but not surprising".
"Zanu-PF has been in power for nearly 30 years and they still want to continue to be on the lead and yet they've got nothing to offer the people of Zimbabwe," he told Al Jazeera.
"I would have expected them to be focusing on real issues - the bread and butter issues - and their time and resources trying to resolve the situation which is bedevilling the country."
Ali said the possibility of Mugabe standing for re-election cannot be ruled out.
"Already he has been campaigning that he be endorsed to be the presidential candidate," he said.
"So whether he's going to be the one on the seat or somebody else that will soon come out, but I'm not surprised with whatever comes out ... because the old man doesn't want to go and this is being reflected by what's been happening."
Critics say Mugabe is responsible for the last decade of economic collapse and political violence in Zimbabwe and Zanu-PF itself has been divided over who should eventually succeed him.
Joice Mujuru, the vice-president and the wife of a former army general, is seen as the front runner to replace him.
But a second camp is led by Emmerson Mnangagwa, the country's defence minister, who local media have long touted as a possible favourite.
Haru Mutasa, Al Jazeera's correspondent in Harare, said that while there was little likelihood of an immediate split, the division could potentially destabilise the party.
"The fear in people's minds is that if Mugabe shouldn't manage to live out his term - or if he steps down for any reason - and he hasn't appointed anyone to take over from him then the factions within Zanu-PF might start squabbling among each other to see who comes out on top," she said.
"The fear is that the groups who want to vie for this position have military backgrounds and could be prepared to do anything to hang on to power."
Despite this, analysts say there is likely to be little overt debate on the subject at the conference.
"There will be no noise during the congress, and there will be no meaningful debate," said Lovemore Madhuku, the chairman of the pro-democracy group National Constitutional Assembly.
Takura Zhangazha, the country director of the Media Institute of Southern Africa, said: "Zanu-PF will come out of the congress still limping ... They won't come out with a pragmatic approach to revitalise the party."
Although the Zanu-PF retains significant support, especially in rural areas, opinion polls suggest that it would probably lose any new election.