By Joshua Franklin and Brian Homewood

ZURICH/BERN (Reuters) - Former FIFA executive committee member Chuck Blazer, a key figure in a U.S. investigation into corruption by soccer officials, on Thursday was banned for life from soccer activities by the sport's governing body.

Blazer, who in 2013 secretly pleaded guilty in the United States to bribery and financial offences, was found by FIFA's ethics committee to have breached rules on loyalty, confidentiality, duty of disclosure, conflicts of interest, offering and accepting gifts and bribery and corruption.

"Mr Blazer committed many and various acts of misconduct continuously and repeatedly during his time as an official in different high-ranking and influential positions at FIFA and CONCACAF (which governs the sport in North and Central America and the Caribbean)," the ethics committee said in statement.

"In his positions as a soccer official, he was a key player in schemes involving the offer, acceptance, payment and receipt of undisclosed and illegal payments, bribes and kickbacks as well as other money-making schemes."

U.S.-based lawyers for Blazer did not immediately respond to a request for comment.

Through a 2013 U.S. plea agreement, Blazer become a cooperating witness in the U.S. probe, which has engulfed FIFA and pressured the governing body's president, Sepp Blatter, to step down.

Blazer agreed to provide prosecutors information, turn over any documents he possessed related to the probe, participate in undercover activities and testify at trial.

The 70-year-old, who has a curly white beard and has in the past tipped the scales at more than 400 lb, is now in hospital with rectal cancer, type 2 diabetes and coronary artery disease.

Blazer was on FIFA's executive committee which awarded the 2018 and 2022 World Cups to Russia and Qatar respectively, a process which is under investigation by Swiss authorities.

Over the past years, as a critical spotlight has been increasingly turned on the organization and the awarding of World Cups, FIFA has handed down bans to a number of officials.

Among them, Asian soccer chief Mohamed Bin Hammam was banned for life for ethics breaches.

FIFA said on Monday Harold Mayne-Nicholls, who led the teams which inspected bids for 2018 and 2022, was banned from all soccer for seven years. He said on Twitter he would appeal.

FIFA has said it is cooperating with the investigations. Qatar and Russia deny wrongdoing and say they are preparing to hold the tournaments on schedule.

(Editing by Alison Williams)