The pictures show Van Hoecke, who came 15th in the men's omnium on Sunday, with his eyes closed being carried by two others, including team mate Jonathan Dufrasne, with his trousers and shirt covered in liquid.
British tabloid the Mirror lightheartedly awarded the gold medal for partying to Van Hoecke when it published the pictures of the latter stages of a night out in London's Mahiki club, but Belgian officials said it was no laughing matter.
"The Belgian Olympic Committee and the Royal Cycling Federation deplore this incident, which fortunately did not affect life in the Olympic Village and athletes trying to rest ahead of their competition," the sporting body said in a statement.
Van Hoecke, 20, had been sent home immediately, the statement said.
Belgian daily Het Laatste Nieuws said Van Hoecke regretted the incident.
"I made a big mistake. I'm happy my parents didn't tell me off. They understand that I needed this," the newspaper quoted him as saying.