LISBON, July 15 (Reuters) - Portugal's government is finalising a strategic plan to explore for raw materials critical to the green transition, where copper could take on a more important role than lithium, the environment and energy minister said on Monday.

Maria da Graca Carvalho said Portugal "fortunately has many critical raw materials for the green transition, such as copper, which is needed for electric cars".

Portugal already has the largest copper mine in the European Union, operated by Toronto-based Lundin Mining. It also produces lithium for the ceramics industry and has large deposits of battery-grade lithium that are in development.

"We have great potential to explore for copper, we already have a great tradition and we will continue to invest," she told reporters on the sidelines of a conference.

"When looking at critical raw materials, we have to consider lithium, but it is not the only one, nor perhaps the most important".

She said the strategic plan should be presented on July 22.

"Based on this strategy, we will define the areas of production for the various critical raw materials," she said, adding that "there may be new concessions".

Europe is aiming to ensure greater security and reduce dependence on imports from countries such as China for materials essential to the green transition.

Portugal's previous government planned to auction licenses for lithium prospecting in six areas in the north and centre of the country.

However concerns about the environmental and social impact of lithium mining from nature preservation groups and local communities have led to multiple delays to the auction, initially planned for 2018.

Asked if the new government intends to proceed with the lithium auction, Carvalho cited the need to see the final strategic plan and base any decision on scientific and technical data. (Reporting by Sergio Goncalves; Editing by Andrei Khalip and Jan Harvey)