Spain and Portugal have denied claims of a pact with Qatar over the voting process for the 2018 and 2022 World Cup.
The countries have launched a joint bid to host the 2018 tournament, while Qatar are in the running for the event four years later.
England, Russia and a further combined bid from Belgium/Netherlands are in the running to host the 2018 finals, while Japan, South Korea, Australia and the USA are hoping to host in 2022.
World governing body FIFA are investigating allegations of collusion and vote exchanging between nations involved in either competition.
Two members of the FIFA executive committee were provisionally suspended last week following allegations they offered to sell their votes to undercover newspaper reporters.
“The Iberian bid already told FIFA last Wednesday that it does not have any agreement with any other bidding nation,” Miguel Angel Lopez, chief executive of the Spanish/Portuguese candidacy, said in a statement.
Lopez added that they had offered their full co-operation to FIFA in their ongoing investigation.
A decision is due to be announced by FIFA as to who will host the upcoming tournaments on 2nd December in Zurich.