Kuwait Football Association official Husain Al Musallam drew FIFA's attention to the presence of Bin Hammam's associates at the AFC headquarters at Kuala Lumpur ahead of the election for a new leader at the 47-member confederation.
FIFA deputy secretary general Markus Kattner said Bin Hammam's direct or indirect involvement in the election would be a breach of the life-ban FIFA had slapped on the Qatari for corruption and bribery.
"We would like to turn your attention to the fact that this lifetime ban from all football related activity imposed on Mr. Bin Hammam specifically prohibits any member or employee of the football family (e.g. member associations, officials etc.) to contact or meet with Mr. Bin Hammam regarding any football related issues," Kattner said in a letter to Qatar Football Association general secretary Saoud Al-Mohannadi.
"In the event Mr. Bin Hammam should visit, attend or meet various AFC members or AFC member associations in order to support specific candidates around the upcoming AFC elections, this would cause a clear and serious breach of the sanction imposed on Mr. Bin Hammam," Kattner added.
"...anyone who fails to comply with a decision passed by a body, a committee or an instance of FIFA, may be sanctioned," the official warned, citing the FIFA disciplinary code.
Four candidates are vying for the AFC top job and two of them - Yousuf Al Serkal of the United Arab Emirates and Thai Worawi Makudi - are known Bin Hammam allies.
Bahrain's Sheikh Salman bin Ebrahim Al Khalifa and Saudi Arabia's Hafez Ibrahim Al Medlej are the two other candidates.