Indian police imposed heavy security and closed several main roads around New Delhi on Wednesday, a day after farmers went on the rampage in the capital, leaving one person dead and dozens injured. 

The violence marked a dramatic escalation in a standoff between the government and thousands of farmers camped out on the outskirts of the city since late November.

The farmers, mostly from northern Indian states including Punjab, want new agricultural reforms scrapped that they fear will leave them at the mercy of big corporations.

On Tuesday -- during annual Republic Day parade -- convoys of farmers on tractors smashed through barricades to converge on the city centre, seeing off police baton charges and volleys of tear gas.

One farmer was killed in what police said was an accident after his tractor overturned after hitting a barricade. At least 86 police were injured, an official statement said. 

Around the city, security forces fought running battles with demonstrators. Farmers also laid into police with branches and metal bars and hijacked buses used to block their convoys.

At the historic Red Fort landmark farmers broke through police lines and put up their own emblem on the flagpole to cheers from the large crowd before being dispersed from the ramparts by security forces.

On one main road, people on rooftops threw petals on the tractor convoys. Elsewhere people cheered and applauded as farmers went past waving Indian flags and blowing horns.

As night fell, the farmers retreated to the camps outside the city where they have been braving Delhi's chilly winter nights since late November.