He used a public meeting in Gloucester to signal his readiness to examine the wider problems facing farmers.
Mr Blair said he would hold talks with farmers' leaders and supermarkets to chart a way ahead for the industry.
But he also told farmers in the audience that supermarkets had "pretty much got an arm-lock on you people at the moment".
Mr Blair said: "I think we need to sit down with the industry and really work out what is the basis on which we want sustainable farming for the long-term.
"And in a sense, what price are we all prepared to pay for that as well."
The Food Standards Agency and the National Farmers' Union have both said the time is right for such a debate.
Mr Blair also promised that the "armlock" which supermarkets appeared to have on farmers' livelihoods would be discussed with industry leaders.
Other key issues to be discussed would be types of farming, diversification and better marketing of produce, he said.
Compensation question
The prime minister paid tribute to the "responsible way" farmers have co-operated with the government over the crisis.
But he rejected calls that the government should compensate those farmers who have suffered but will not receive recompense.
He said no government had ever paid compensation for "consequential losses".
"If you are not careful, these build up very, very considerably," he said.
Mr Blair, who arrived late for the Gloucester meeting after being stuck in a traffic jam and was barracked by protestors, called farmers the "custodians of the countryside".
He said the current policy was to pay compensation to farmers for slaughtered animals with cash drawn from European agro-money funds. He added that the full scale of losses was not yet known.
Mr Blair added that it looked like the outbreak of foot-and-mouth which has devastated the farming industry could be traced back to a single origin, making it easier to trace the movements of affected animals.
"It is too early to say whether we can be sanguine about this but that will make a big difference to the eventual consequential losses there are and therefore our attitude to it," he said.