Major European fishing states voiced deep reservations Tuesday over a controversial European Commission proposal to reform the sector in a bid to replenish fish stocks within four years.

EU fisheries commissioner Maria Damanaki presented to fisheries ministers meeting in Brussels a sweeping proposal that includes a system to allow fishermen to trade their catch quotas at the national level.

Her plan would also ban by 2016 the practice of throwing discarded fish overboard, providing fishermen incentives to either transform those fish into flour, freeze them or donate them to food pantries.

While Britain, Denmark and Sweden welcomed her proposal, the European Union's two biggest fishing states, Spain and France, criticised key elements.

"Decisions that would be too radical would lead to the closure of fishing in Europem" French Agriculture Minister Bruno Le Maire told reporters.

He said the quota system was unacceptable in its proposed form because it would lead to a consolidation of the sector "in the hands of a few big industrial groups."

But he said he was not outright rejecting the quota idea, adding that he would study proposed safeguards including an exemption for boats smaller than 12 metres.

Le Maire and Spanish counterpart Rosa Aguilar said the plan to ban the practice of throwing out discarded fish was not realistic.

Aguilar also voiced concerns about the goal to limit fishing to achieve a maximum sustainable yield of fish stocks in 2015. She said the target date should be pushed back to 2020.

"Any other date would have considerable social and economic repercussions," she said.