Students and other opponents of President Nicolas Maduro are demanding he quit over grievances including high inflation, shocking levels of violent crime, shortages of basic food, and what they say is his repression of political rivals.
The protests are the biggest challenge to Mr Maduro's 10-month-old administration, although there is no sign they could topple him or affect the nation's oil shipments.
Among the latest world figures to speak out about the unrest, Pope Francis said he was "particularly concerned" by recent events.
He added: "I sincerely hope the violence and hostility ends as soon as possible and the Venezuelan people act to foster national reconciliation through mutual forgiveness and sincere dialogue."
Mr Ban called for "concrete gestures by all parties to reduce polarisation" and engage in dialogue.