CARACAS, Venezuela (Reuters) -- Hundreds of thousands of people on Saturday marched in Caracas to support opposition presidential candidate Manuel Rosales, whose populist campaign has focused on reducing crime and redistributing oil wealth.

Rosales, governor of the oil-rich Zulia state, trails leftist President Hugo Chavez by around 20 percentage points in most private polls ahead of the Dec. 3 election.

Opposition sympathizers donning Venezuela's signature red, yellow and blue patriotic colors joined the march, which spanned some 12 miles (20 km) across most of the capital city.

Opposition leaders also accuse the Chavez government of drawing up blacklists to intimidate voters and requiring public employees to join pro-Chavez campaign activities.

State television showed images on Saturday of what appeared to be thousands of pro-Chavez oil workers gathered to support the energy minister in the eastern city of Puerto La Cruz, where Chavez was scheduled to appear.

Chavez has built up support among the poor by using oil revenues to finance a massive social development campaign that has expanded access to health care and education.

Most polls released in recent weeks show Rosales far behind Chavez despite having united a fractured opposition that failed to oust the former army officer through a botched coup, a two-month oil strike and a recall campaign.

Chavez was first elected in 1998 and again in 2000 on promises to end poverty.