Move Forward Party (MFP) MP and activist Rangsiman Rome said it is a public authority's job to investigate 86 companies that allegedly received money from the narcotics trade.
Mr Rangsiman was responding yesterday to a call by Senator Upakit Pachiriyangkun, who urged him on Monday to take action against the suspected firms. The senator submitted the list of companies to prosecutors earlier after finding himself in the line of fire.
During a general debate in the House of Representatives last month, Mr Rangsiman made similar allegations against an unnamed senator -- presumed to be Sen Upakit, a long-time business partner of Myanmar tycoon Tun Min Latt who controlled a drug network.
Mr Rangsiman claimed he had strong evidence -- including the senator's financial transactions, chat messages with a company linked to the illegal drug trade, and confessions from multiple suspects -- to back up his claim the man took drug money as bribes.
Protesting his innocence, Sen Upakit said he wanted Mr Rangsiman to launch a broader investigation in the interests of fairness, rather than target him alone.
Mr Rangsiman said he was aware Sen Upakit, 61, had submitted the list of names. He said the help of any senator would be welcome in such a probe.
However, he cautioned that more evidence would be needed as the list per se is not sufficient.
After the general debate, the senator reported to the Narcotics Suppression Bureau's Division 3 on March 27 and denied colluding in money laundering and a related criminal charge. He was questioned by police and public prosecutors in line with Section 134 of the Criminal Code.
He was later charged with colluding in money laundering and involvement in a transnational criminal organisation while serving as a senator.
The senator was then fingerprinted. However, he was not named in a summons or any arrest warrant and was subsequently released.
He was instructed to report to police again on April 17 for further questioning.
On March 17, Sen Upakit held a press briefing to counter Mr Rangsiman's claims he had ties to the narcotics trade.