The arrests were made on Sunday after a raid was conducted in a godown at Balkum here, Sr Police Inspector Niteen Thackeray of Thane Crime Branch said.
The accused were found collecting waste cement unloaded at the railway yards at Kalwa, Thane, Kalyan and Mulund railway stations.
They used to package the collected cement in gunny bags with brand names and sell them at regular prices, police said.
Following the raid, police seized many cement and empty bags valued at Rs 76,450 and registered offences under sections 420 rw 34 against the culprits.
Those arrested are Gautam alias Rushi Uday Singh, 22, Ramu Nandram Rao, 50, Vinodkumar Jairaj Gautam, 42, Rajeshkumar Gautam, 35 and Janardhan Srivandam Gautam, 28, police said.