Tens of thousands of Zimbabweans have marched through the capital Harare in support of veteran President Robert Mugabe, but their number fell short of the ruling party's goal of attracting a million people.

Demonstrators were shipped in from all over Zimbabwe for Wednesday's march, organised by the Zanu-PF's youth wing.

They sang pro-Mugabe songs as they spilled out of buses in downtown Harare, a show of force to counter demonstration by the opposition last month calling for the president's resignation.

Speaking at the rally, the 92-year-old Mugabe denounced as "treasonous" factions in his party feuding over who should succeed him.

"There should never be little groups to promote so and so. Those little groups are treasonous groups, they spoil the party," Mugabe told his supporters.

"Let us not hear discordant voices from whomsoever. All this thing about factions is new to us, it destabilises the party," said Mugabe, touting the march as a "great revolutionary act" by young party members.

Critics of Mugabe said organising the march costs at least half a million dollars - money better spent to fight poverty.

"That effort is a waste of time, a waste of energy, that effort is a waste of resources," Nelson Chamisa of the opposition party Movement for Democratic Change (MDC), told Al Jazeera.

Factional infighting

As senior members of Zanu-PF manoeuvre for advantage in a post-Mugabe era, two factions have emerged - one linked to Vice President Emmerson Mnangagwa and one to Mugabe's wife Grace.

First lady Grace Mugabe told the crowd earlier that the veteran leader was irreplaceable and the unifying force in Zanu-PF who would continue to lead Zimbabwe even in death.

Mugabe is the only leader the southern African nation has known since independence from Britain in 1980.

He has said he wants to live to 100 and remains fit, denying local media reports that he has prostate cancer.

Mugabe also said local private media calling on him to step down should "go hang", adding that the opposition MDC also wanted him to resign because they feared he would defeat them again in elections in 2018.

Mugabe's decades in office have been marked by economic decline, repression of dissent, vote-rigging and mass unemployment and emigration.