Several suspects arrested in Spain as part of a probe into Chinese gangs suspected of laundering tens of millions of euros each year appeared in court for questioning Wednesday.

Ten of the over 80 people detained in raids carried out on Tuesday across Spain arrived at the central Madrid court in two police vans which were escorted by a police patrol car.

The court could hear from more suspects later on Wednesday depending on how quickly the first batch is questioned, a court official said.

Among those arrested was Chinese businessman and gallery owner Gao Ping who is suspected of being one of the leaders of the network, Spanish porn actor Nacho Vidal and Jose Borras, a local city councillor from Fuenlabrada in southern Madrid.

So far, 83 people have been detained in the operation, including 58 Chinese nationals, 17 Spaniards and eight people from other countries, national police director Ignacio Cosido told a press conference.

One suspect was detained in Germany and more arrests could be made outside of Spain in the coming days as the operation remains open, Cosido added.

"We are talking about a historic operation, a very important operation in the fight against economic delinquency," he said.

Over 500 police took part in "Operation Emperor". They seized around 10 million euros ($13 million) in cash in dozens of raids across the country over the past two days as well as some 200 vehicles, guns, jewels and works of art.

The authorities also froze the bank accounts of more than 120 people.

The investigation began in 2009 and focused on the Cobo Calleja industrial zone in Fuenlabrada, considered the biggest Chinese wholesale hub in Europe.

The industrial zone is known as a source of cheap goods imported from China and sells shoes, clothes, jewellery and other wholesale goods to Spanish businesses, as well as distributing them across Europe.

"This has been a very long operation, an operation that demanded a lot of work," said Cosido.

Spanish prosecutors said the racket was made up of traders who sold contraband goods in Spain, laundered the money and transferred it to China by train and car, using front companies such as karaoke bars and restaurants.

The gang is also suspected of channelling money from rackets involving prostitution and extortion to tax havens with the help of Spanish and Israeli intermediaries.

The network laundered between 200 and 300 million euros a year by dodging taxes, bribing officials and forging documents, top anti-corruption prosecutor Antonio Salinas said Tuesday when the arrests were first announced.

Gao reportedly owns several warehouses in Cobo Calleja industrial zone as well as a contemporary art gallery in Madrid near the Queen Sofia Museum.

Vidal, an international porn star credited in titles such as "Sexcapades", ran a company suspected of taking part in the money-laundering.

Chinese firms in the Cobo Calleja industrial zone officially do some 870 million euros in trade a year, according to the town hall in Fuenlabrada.

Of the 800 businesses there, it said 377 were Chinese-run, employing 3,000 of the total 10,000 people working in the area.