Mohamed bin Hammam intends to fight to clear his name after Fifa opened investigation proceedings against him over alleged financial mismanagement.
World football's governing body is looking into the Qatari administrator's time as Asian Football Confederation (AFC) president.
The one-time Fifa presidential candidate saw a bribery ban overturned in July due to insufficient evidence.
But he was suspended for 90 days by Fifa, extending an 30-day AFC ban.
Bin Hammam was accused of attempting to buy votes ahead of last year's Fifa presidential election.
Fifa had banned him from "any kind of football-related activity at national and international level for life".
But in July the Court of Arbitration for Sport (Cas) said there was insufficient evidence to support the ban.
In a letter to AFC committee members Bin Hamman says: "My legal team has filed an immediate response to the actions of the AFC and FIFA in relation to my latest politically-motivated ban.
"I will announce further steps very shortly to challenge this clear abuse of power and process at the hand of FIFA."
A recent report from auditors PWC into the accounts of the AFC showed payments to several individuals. Bin Hammam details the reasons why the payments were made and states they were from his own accounts.
He outlines five payments and insists all the payments were for welfare reasons.