Video report by ITV News Correspondent John Ray

Venezuelan opposition leader Juan Guaido has set a deadline to bring humanitarian aid into the country, as thousands of civilians protest the leadership of socialist President Nicolas Maduro.

Guaido said he's mobilising caravans of Venezuelans to get the emergency food and medicine across the border in Colombia - which has so far been blocked by the military.

Speaking before masses of supporters he set a deadline as February 23 and restated his appeal to Venezuela's military, which so far has remained loyal to Maduro.

Maduro also rallied supporters at rival demonstrations following more than a month of pressure led by the opposition lawmaker.

Thousands of opposition supporters are hoping demonstrations will force the military into backing them. Credit: AP

It comes as Britain joins America in committing to provide medicine and clean water to civilians caught up in Venezuela's economic collapse - assisting with £6.5 million in aid.

The Department for International Development (DfID) said the assistance would be used to support humanitarian agencies working in the region to mitigate the crisis.

There is currently emergency food and medicine from the United States warehoused on the Colombian border town of Cucuta but Maduro has been using backing from the military to block the aid.

President Maduro has been using the military to block aid, which he thinks is part of a US coup. Credit: AP

While opponent Guaido has vowed to deliver it to those who need it, his strategy for outmaneuvering Maduro remains unclear.

Guaido in January declared presidential powers, arguing Maduro’s re-election was a sham, and called on soldiers to back a return to democracy.

He’s garnered broad international support and has drawn masses into the streets for protests, which have sometimes turned violent.

Earlier this month Britain joined other leading European nations in recognising the opposition leader as the country's interim president after Maduro rejected demands for fresh elections.

Juan Guaido, who has declared himself the interim president, is hoping to topple the government. Credit: AP

The socialist president says humanitarian aid provided by Western nations is part of US-led coup that aims to topple him.

Venezuela’s military last week barricaded a key bridge between Venezuela and Colombia in an apparent attempt to keep the humanitarian aid from entering.

International Development Secretary Penny Mordaunt called for aid agencies to be given "unhindered access" to those suffering as a result of the crisis, which has seen hyperinflation of more than one million per cent.

Venezuela's socialist president Nicolas Maduro is facing an economic crisis in his country. Credit: AP

"I am deeply disturbed by the awful scenes of suffering in Venezuela as a result of the Maduro regime's reckless mismanagement, with families resorting to eating rotting food to try to survive," she said.

"UK aid will provide life-saving treatment to malnourished children, immunisations against deadly diseases and access to clean water and sanitation.

"While the UK has stepped up by providing urgent relief, all parties must immediately recognise the severity of the crisis and allow unhindered access for aid agencies."