"We categorically deny making any agreement or alliance with another bid on the voting to decide the hosting of the 2018 and 2022 World Cups," Portuguese Football Federation chief Gilberto Madail was quoted as saying by the Lusa news agency.
Portugal and Spain are jointly bidding to host the 2018 World Cup along with England, Russia and Belgium/Netherlands while Qatar, Japan, South Korea, the United States and Australia are candidates for 2022.
The vote to decide the hosts of the two tournaments is due to take place in Zurich on December 2.
FIFA on Wednesday said in a statement it had opened an investigation into alleged agreements between bid committees, which it expected to complete by mid-November.
Britain's Daily Telegraph newspaper on Thursday cited unnamed sources saying FIFA was investigating the Iberian and Qatari bids for alleged collusion and if found guilty they would be expelled from the selection process.
ALLEGED DEAL
The Telegraph had reported in September that rumours of collusion between Portugal-Spain and Qatar were widespread.
World soccer's governing body has not commented on whether the two bids are being investigated.
"We received with surprise and indignation the analysis that FIFA's ethics committee may conduct on a rumour... circulated in September in the English media about an alleged deal between the Iberian and the Qatari bids for hosting the World Cup," Madail said in the Lusa story which was also posted on the Portuguese federation's own website).
Madail questioned the timing of the allegations in Thursday's Telegraph, which appeared the day after two members of FIFA's executive committee were provisionally suspended by the ethics committee for alleged vote-selling.
Nigeria's Amos Adamu and Reynald Temarii of Tahiti are alleged to have offered to sell their votes on who should host the World Cup when approached by journalists from Britain's Sunday Times newspaper posing as lobbyists for an American consortium.
"It is odd that there is an attempt to launch completely unfounded suspicions about the Iberian bid at a time when there are news reports about alleged vote-selling for the 2018 and 2022 World Cups involving other bids," Madail added.
