The ministers were meeting in Merida, an agricultural heartland in Spain's Extremadura region, where thousands of Spanish farmers had gathered amid the town's Roman ruins to stage noisy protests against any reduction in farm subsidies.
The Common Agricultural Policy (CAP) consumes about 40% of the 27-nation EU's €120 billion ($145.8 billion) annual budget.
But with public finances under extreme pressure as Europe tries to tackle the current economic crisis, many question whether the EU can still afford to devote so much cash to farming.
France received €9.5 billion euros from the CAP last year - more than any other EU country - and is leading the push to maintain current farm spending levels.
"We have to protect the budget we have now," France's Agriculture Minister Bruno Le Maire said at the meeting.
But Paris faces opposition from countries including Britain, which argues that more pressing priorities like competitiveness and climate change demand a shift in EU spending.
"You can't run away from the fact that Europe's run out of money, so we have to prioritise here," UK Agriculture Minister Caroline Spelman told reporters before the meeting.
"I could not support a conclusion that suggests the current levels of CAP support must be protected," she told fellow ministers on Tuesday.
While Britain lacks obvious allies going into the reform talks, Spelman said she believes the stark economic realities facing Europe will attract supporters to her way of thinking.
The position of Germany, which pays more into the EU's coffers than any other country, will be a key factor in the talks.
Behind the scenes in Merida, the German delegation said that they were concerned by Britain's stance. Ilse Aigner, the country's farm minister, told reporters that the CAP budget must remain stable after 2013.
But it was not clear yet whether her view was shared by the finance ministry in Berlin.
While most countries oppose Britain's stance on the budget, there is no clear consensus between France, Germany and others on how the money should be spent.
All of the countries that joined the EU since 2004 want to see an end to the current criteria for allocating direct subsidies to farmers.
Linked to historical production levels between 2000 and 2002, the present system sees farmers in Western Europe receive much higher subsidies than producers in countries such as Poland and Hungary.
France and Germany - traditional partners in EU farm policy discussions - disagree on how heavily the EU should regulate agricultural markets.
"On market regulation the French want to go much further than we do," a senior German government official in Merida said.
If these countries can iron out their differences before the reform talks enter full swing next year, they will create a formidable negotiating bloc.
"If you count French, German and Polish agriculture together, you already have something very significant in the overall balance," Le Maire said.
(EurActiv with Reuters.)