In recent times, the quotas have been split informally between Portugal and Spain based on historical captures - with 70% going to the former and 30% to the latter.


Spain's government, however, denied on Saturday that there are any set criteria.


"It's a subject that has been the subject of many political and technical discussions, but in which Portugal and Spain do not share the same point of view," Cristas said, during a visit to a ship that is preparing to assess the sardine stocks. "We believe that the history of more recent years should be applied."


If the European Commission were to take over the division, that would be the criterion used, she argued. However, she added, neither country is keen for the commission to take over the process.


When sardine is scarcer, it is more difficult to reach a consensus on the criteria for the division, she said.