A South African trade union threatened on Tuesday to take mass action against the EU over a citrus dispute.

The Food and Allied Workers Union (FAWU) said it is in full support to concerns raised by South Africa's citrus industry that the EU is using the so-called "black spot" in oranges to limit the imports of the country's citrus.

The European Commission has recently brought in stricter import requirements for South African citrus fruit due to the "black spot", a fungus that could affect crops in Europe.

The FAWU said the move is "nothing but non-tariff, if not technical, barrier to trade, thereby excluding competitive, in quality and price, oranges and other citrus products from South Africa".

Eu imported 600,000 tonnes of citrus from South Africa in 2013, about 40 percent of the country's total production.

The fruit contributes around 6 billion rands (about 566 million U.S. dollars) to South Africa's gross domestic product.