The Competition Commission is looking into whether gas stations on Crete are working together to keep fuel prices artificially high.
In checks held at Cretan service station associations on Tuesday, the competition watchdog confiscated files and minutes from their meetings.
Gas station owners on Greece?s largest island recognize the lack of competition in their district but blame it on rigid conditions in the wholesale fuel market.
They have called on the government to impose a price ceiling on wholesale fuel prices by the end of the month in a bid to help lower their retail prices, threatening to otherwise launch strike action.
The island often has among the highest gas prices in Greece.
An investigation by the Competition Commission into Crete?s fuel market was initially launched in 2009 but a decision has yet to be reached.