The warning was issued by Prime Minister Nguyen Xuan Phuc, after the Communist Party Central Committee issued an official warning against Muon last month and requested that the government impose further punishment.
Muon, 65, was found to have committed violations in advising government leaders on the privatization of and state capital divestment from several enterprises under the Ministry of Transport while he was the deputy head of the Government Office between 2010 and 2015, said the inspection committee.
His violations, as well as those of the ministry's Party Committee and other relevant officials, "caused great losses to the state budget and assets" and "negatively affect the reputation of the party and the transport sector," the inspection committee said in April, without revealing specific numbers.
Vietnam's Communist Party has four modes of punishment against members: reprimand, warning, demotion and expulsion.
Several other top officials have been disciplined regarding the case.
Last month, former Deputy PM Vu Van Ninh, who served the post between 2011 and 2016, received an official warning for signing documents approving the privatization of and divestment from some enterprises under the transport ministry without following regulations set by the party and the government.
His violations involved wrongful divestment at Nha Trang Port JSC in the central province of Khanh Hoa and privatization at Vietnam Airports Corporation.
For related violations, former Deputy Minister of Transport Nguyen Hong Truong lost his party position while three other deputy ministers received reprimands and warning last month.