More than $16 million in cash and luxury watches were seized at an airport in Brazil in the luggage of a delegation accompanying the son of the president Equatorial Guinea, local media reported.

Teodorin Nguema Obiang, vice president of Equatorial Guinea and son of its longtime president, Teodoro Obiang Nguema, arrived on Friday on a private plane at Viracapos airport near Sao Paulo as part of an 11 person delegation.

O Estado de Sao Paulo reported on its website late on Saturday that federal police found $1.5 million in cash in one bag and watches worth an estimated $15 million in another.

TV Globo said Obiang was the only member of the delegation who had diplomatic immunity as the group was not on an official mission.

The bags of other delegation members were inspected as Obiang waited outside in a car, it said.

Brazilian law prohibits people from entering the country with more than 10,000 reais, or about $2,400, in cash.

Brazil's foreign ministry told AFP that it was “in permanent coordination with the federal police and the customs service over the case and to decide what measures should be taken".

The embassy of Equatorial Guinea in Brasilia did not respond to questions about the matter.

O Estado de Sao Paulo quoted a diplomatic source from Equatorial Guinea as saying the money was to pay for medical treatment Obiang was to undergo in Sao Paulo.

As for the watches, they were for the “personal use” of the president's son, and were engraved with his initials, the report said.

Accused of using public funds to support a lavish lifestyle, Obiang was sentenced in France to a three year suspended sentence in October 2017 for money-laundering.

He has visited Brazil several times, attending the 2015 Carnival in Rio de Janeiro when a samba school won top honours for an Equatorial Guinea-themed parade but was heavily criticised because of alleged funding for it by the Obiang regime.

Obiang, an autocrat with broad powers to rule by decree, has been in power for 38 years.