From China Digital Space
有关部门 (yǒuguān bùmén): relevant departmentrequest for information may be turned down and the person seeking the information directed to ask the “relevant department” without identifying which department that is.
The Relevant Department is the most powerful Chinese governmental body since the beginning of time. The Relevant Department takes care of everything other departments are unwilling to tackle, and is quoted by the media more than any other department. It is also the most inscrutable governmental body in the world. The Relevant Department does not appear under normal circumstances, and you will not be able to find it. Over the years, the Relevant Department has solved many problems and eased many worries for the government and the press.
On Sina Weibo, a fellow netizen jokingly asked a relevant department to investigate Hu Xijin, a journalist and editor of the state-owned Global Times:
魏克漫画: Could the relevant department please look into this person named Hu Xijin? He spends all day trying to fool people to be patriotic, yet he is engaged in activities that hurt the country.