One of those arrested admitted to the Belgian authorities that he was involved in match-rigging in Finland.
In Germany, media also reported that a high-profile player had been questioned by police over alleged match-fixing although Munich prosecutors said they had not listed anybody as accused.
However, the Belgian authorities confirmed that they are "looking in to" media reports that the same people are behind the alleged betting scandals in both Belgium and Germany.
"We are working with the German authorities and indeed Europol in general in relation to this," Lieve Pellens, spokeswoman for the Federal Prosecutor said.
Pellens described Thursday as "the turning point in the investigation" adding that she expected charges to be laid on Friday.
Former player Olivier Suray admitted to being involved in match-fixing in Finland with AC Alliansi.
Finnish Football Association chairman Pekka Hamalainen welcomed the arrests.
"This is positive news. Already in July we were in contact with the police in Helsinki, and they were in contact with Belgium," he said.
CHINESE BUSINESSMAN
In Belgium an international arrest warrant has been issued for a Chinese businessman and a leading players' agent, wanted for questioning.
The other six arrests include a club chairman, a former club chairman, two players, a club lawyer and another agent.
The arrest warrants were issued for Ye Zheyun, believed to be back in China and Pietro Alatta, Belgium's most prominent agent, who is reported to be in Mauritius.
Described by police as the key player, Ye Zheyun was arrested in Brussels in November, but later released.
Ye once owned a stake in Alliansi, but late last year the club broke all ties with Ye, saying he had not fulfilled the financial terms of his June takeover.
Meanwhile, Filippo Gaone, chairman of Belgian first division club La Louviere, was arrested and had his home and business searched. La Louviere's lawyer, Laurent Denis, also had his business raided.
Chris De Nijn, the former Lierse chairman, was also brought in for questioning.
Excelsior Mouscron sacked their coach Paul Put last month after he admitted he fixed two matches while in charge at Lierse last season. He said his family had been threatened.
INFLUENCE RESULTS
Players Marius Mitu and Laurent Delorge were sacked by their new club Anderlecht after they admitted to club officials they had helped influence results last season with Lierse.
A total of five Belgian first division clubs are under investigation by police who opened their enquiry in November after internet betting exchange Betfair logged heavy betting patterns for La Louviere's 3-1 win over St Truiden on Oct. 29.
La Louviere deny any involvement.
St Truiden, who also deny involvement, had three players arrested during training last week. All three were later released pending further enquiries.
The club have also instructed players to sign a declaration that they will not bet on any of their games or give out team information.
The Belgian Football Association launched their own match-fixing investigation last month after a programme by Flemish national broadcaster VRT alleged seven first division matches this season were fixed.
Finnish public television is set to broadcast a programme later on Thursday on investigations into possible match-fixing in Europe.
It will include a look at a game in July last year when AC Allianssi lost 8-0 in a match that attracted unusually heavy betting. Ye was involved with the club at the time.
A Finnish disciplinary committee found no evidence that game was fixed, but fined the team.
On Wednesday a second match-rigging scandal in German soccer was revealed with prosecutors in Munich investigating media reports that several Bundesliga players, among them a German international, had been in contact with a betting ring.
Four people were arrested in Germany last week after an investigation by Frankfurt prosecutors into alleged match-rigging in the second division and a regional league.
(addional reporting by Rex Merryfield in Helsinki and Patrick Vignal in Paris)
