Rider who race in the Paris-Nice stage race next week risk stiff suspensions, fines and bans from the Olympics and the World Championships, the sport's governing body the International Cycling Union announced on Tuesday.
The riders themselves have asked for written assurances from team bosses that any fines and their salaries if they are suspended would be picked up by the teams.
However, the UCI made plain in an email sent to the 17 ProTour teams set to take part that the riders risked serious punishments aside from the bans, suspensions of up to six months and fines of anything up to 10,000 Swiss francs.
"Our riders received this letter by email today (Tuesday)," admitted Rabobank's sports director Eric Breukink. "Our riders are frightened."
Earlier on Tuesday organisers of the race reached agreement over contracts for the event after weeks of uncertainty, team body the AIGCP said.
It had looked as if the first major European stage race of the season would go ahead under a cloud after organisers Amaury Sports Organisation (ASO) controversially opted to hold it under the aegis of the French federation, and not the UCI.
The latter promptly warned sanctions against participants, in the wake of major race organisers, such as Tour de France and Paris-Nice organiser ASO, splitting from the UCI's Pro Tour series amid a complex contractual dispute.
The UCI also refused on Tuesday for a meeting between their president Pat McQuaid with Jean Pitallier, president of the French Cycling Federation (FFC), and Sports Minister Bernard Laporte this Friday.
"Under these circumstances, the UCI president is not going to say yes to the invitation by the FFC unless the Paris-Nice race agrees to come under the normal rules and regulations," it said in a statement.
"It therefore believes that it is not an opportune time to meet the president of FFC, even in the presence of the Sports Minister Bernard Laporte."
AIGCP said the ASO had accepted to make some changes to team contracts for the race.
"My role was to present the 20 team principals (three are not ProTour outfits) with two questions," explained Eric Boyer, chairman of AIGCP, who warned the UCI "it would be a mistake" to suspend any rider taking part in next week's event.
"First, do you intend to participate in the Paris-Nice? The reply was unanimously 'yes.'
"Then, do you accept the contractual conditions? There, it was a question of 'yes, but.' So we asked for some amendments to the contract."
Those will include acceptance that the French Olympic conciliation body CNOSF can step in as arbiter in the event of disagreements.
"The decision of the teams to participate in the Paris-Nice is linked to their wish to guarantee the interests of their sponsors as well as their sporting interests and those of their riders," a AIGCP statement read.
The AIGCP also called on all parties concerned to engage in a "structured dialogue" to prevent a repeat of the fallout which has marred the run-up to the race.