The European Union should start paying all its trainees at delegations abroad, the European Ombudsman said today, judging that the current practice of unpaid internships unfairly favoured a privileged few.

The ombudsman, which investigates complaints at EU bodies, said the European External Action Service (EEAS) employed some 800 unpaid trainees at its delegations worldwide.

The EEAS had a staff of 4,189 at the end of 2015, with 2,261 in its various delegations in 139 countries.

"The trainees must cover all of their costs including accommodation, travel and health insurance, a system which clearly discriminates against many young people with limited means," the Ombudsman said.

Spaniard Pau Petit, 27, worked for the EEAS office in Geneva for half a year without being paid or insured.

"When I did my internship, I lost 7kg (15lb) of weight because Geneva is just such an expensive place," Petit told Reuters.

"The EEAS also make you sign a contract which says they are not responsible for any problems you may run into," he added.

Petit will take part in a planned global protest by unpaid interns in cities including Brussels, Geneva, Vienna and New York.

While the ombudsman's recommendations are not legally binding, its advice is followed in the majority of cases.

The EEAS said it had taken note of the report and was studying its options.