TWO directors of a controversy-plagued Victorian private college for international students allegedly blackmailed an Indian student who complained about the college's standards.

The revelations raise questions about the Baillieu government's vow to clean up the industry, with at least one of the men facing criminal charges, Kanwal Singh, still working at and managing the South Pacific Institute in Melbourne's CBD.

Questions have arisen over the Baillieu government's vow to clean up private colleges that attract thousands of international students every year.

The Indian-born Kanwal Singh, his fellow South Pacific Institute director Gurvinder Singh, who is also an Indian national and a third man, Ayush Gupta, were recently charged by the Victoria Police with two counts of making an unwarranted demand on a person with menace.

The charges relate to allegations that the trio threatened a student to get him to retract complaints he had made in 2009 about the South Pacific Institute.