France's powerful farming union on Monday threatened a week or more of protest action as it was poised to meet with Prime Minister Gabriel Attal.
The unions have demanded concrete government action to address their grievances, which they say include excessive financial charges and environmental protection rules.
The growing anger of farmers, some of whom have already taken to direct action to express their frustration, is shaping up to be the first major challenge of President Emmanuel Macron's newly appointed government.
Hours before its meeting with Attal, scheduled for 6:00 pm (1700 GMT), the FNSEA union's leader, Arnaud Rousseau, said that "there will be a certain number of protests today, all this week, and for as long as necessary".
The meeting with Attal comes after France's agriculture minister announced that a long-delayed reform package had again been postponed.
This week's protests would affect every part of France, Rousseau told the France Inter broadcaster.
"Tension is rising strongly, which is why we need concrete measures," he said.
The Young Farmers union leader Arnaud Gaillot -- who is also invited to Monday's meeting -- told France 2 television that "we could be on the eve of a massive farmers' movement" if the government's response was not deemed satisfactory.
Over the weekend, Attal insisted that he was on the side of the farmers.
"Our farmers are not bandits, polluters, people who torture animals, as we sometimes hear," he told a meeting on Saturday in the southern Rhone region.
The latest action by farmers in the southern Occitanie region gave a measure of their anger.
They started a blockade of the A64 motorway late on Thursday at Carbonne, around 45 kilometres (28 miles) southwest of Toulouse.
In addition to financial charges and environmental protection rules, farmers are also angry about progressive tax increases on the non-road-use diesel that is essential to their work.
Similar issues have led farmers in other European nations to also take action.
Fleets of tractors have brought traffic to a standstill in Germany and Romania, and farmers have also protested in the Netherlands and Poland.
They all face the challenge of inflation -- caused in part by Russia's invasion of Ukraine -- and what some see as unfair competition from Ukrainian agricultural imports.
In Britain on Monday, fruit and vegetable producers will again demonstrate in front of parliament against what they say are the unfair terms of their contracts with the main supermarkets.
The French government's relations with the sector have not been helped by the repeated postponement of farming reforms first announced by Macron more than a year ago.
Agriculture Minister Marc Fesneau announced yet another delay Sunday to a package that had been due to go before the government later this week.
"Give us a few weeks," he told RTL radio and other news media.
More work needed to be done to simplify the measures, he said, an issue raised by many of the farmers currently protesting.
In comments to AFP, FNSEA vice-president Luc Smessaert made it clear they would need to hear "very concrete" measures.
They want an end to what they call the excessive "copy-pasting" of European norms into the French system -- and for the full implementation of a 2021 law aimed at protecting farmers' wages.
Less than five months out from the European elections, opposition parties are already courting the farmers' vote.
Political leaders on all sides have leapt to the defence of farmers over the issue of rising diesel costs.
And if the FNSEA does not emerge satisfied from its meeting on Monday, they have not ruled out action to hammer home their grievances.
There are expectations that Macron's visit to the annual Agriculture Show in Paris -- which begins February 24 and has historically seen farmers speak their mind directly to French leaders -- might not go smoothly.
