The ten persons arrested, included a part-time worker in the Income Tax department in Chennai, Superintendent of Police (South) T.Baivarasamy told PTI.
They were produced before a local court which remanded them to judicial custody for ten days, he said.
Police had earlier arrested four persons after labour leader Udayakumar was abducted and abandoned at Walajapet in Tamil Nadu.
The accused had posed as sleuths of Income Tax department and took him in a car from here to Chennai on April 6.
The abduction was suspected to be for ransom.