Thousands of Indian farmers riding tractors attempted to resume their push towards New Delhi on Wednesday after failing to reach a deal with the government on their demands for higher crop prices.

The protest hopes to replicate the year-long siege of highways into the capital that pressured Prime Minister Narendra Modi's government into abandoning its agricultural reform plans in 2021.

Police have kept a miles-long column of farmers atop agricultural machinery at bay since last week near the small village of Shambhu, several hours' drive north of their intended destination.

Protesters again stared down efforts to disperse them with tear gas barrages and have vowed to push through a fearsome blockade of metal spikes and concrete barricades erected to halt their progress.

"We assure you that we will break the barriers," farmer Jagmohan Singh, 45, said

"Once we break it, we will only stop again in Delhi."

Anticipating a fresh effort to push past their roadblocks, police dropped tear gas on the roadside protest encampment from drones flying overhead.

Farmers responded by distributing goggles and trying to bring down the aircraft by targeting them with slingshots and flying kites to obstruct their flight paths.

They have also brought bulldozers and excavators to the protest site, with the intention of charging through police barricades at an opportune moment.

Police in Haryana state warned owners not to provide the protesters with earthmovers, saying that they would be held criminally liable if the vehicles harmed officers.

A police statement denied reports broadcast by demonstrators that one farmer had been killed, and said a dozen police officers had been injured, some after being hit by sticks and stones.

Farm unions are demanding a law to set a minimum price on all crops, expanding a government scheme that already exists for staples including rice and wheat.

They have also demanded other concessions including the waiving of loans and universal pensions for farmers aged 60 and above. (AFP)