The "Love the Commerce Ministry" group is being led by former permanent secretaries Charae Jutharattanakul, Krirk-krai Jirapaet and Karun Kittistaporn, and the former directors-general of several departments. It said said they would be on the main stage of the People's Democratic Reform Committee rally to lend their support to the anyti-government movement.
Other retired officials scheduled to take part include Oranuj Osatanonda, Adul Vinaiphat, Boontipa Simasakul and Chantra Punariksha.
Mr Yangyong condemned their decision, saying they were not qualified to use the "Love the Commerce Ministry" name.
Mr Yanyong, himself a former Commerce permanent secretary, said the former officials had never shown interest in helping the ministry since they retired.
Some had faced criticism about transparency in releasing rice stocks under the rice pledging scheme, he said, adding that he believed that their movement was politically motivated to sabotage the rice project.
Some former officials left rice problems unsolved and had never showed responsibility, and some were now advising rice exporters, he added.
Mr Yanyong said the former officials could not claim that they loved the ministry more than active officials, as they also have the same dignity as those who have retired.