The qualifying rounds for next season's Champions League and Europa League are due to be played between August 8 and October 1 but rapidly changing travel restrictions around Europe are making them difficult to organise.
UEFA said on Thursday that Greece, Cyprus, Hungary and Poland would provide "neutral venue hubs". They would make stadiums available on scheduled match dates and their authorities would also offer a travel corridor so games could be played without restrictions.
In guidelines published on Tuesday, UEFA said that home clubs must propose an alternative venue in a neutral country if travel restrictions make it impossible to play in the allotted venue.
Home clubs will forfeit matches if they fail to inform UEFA of restrictions, or if restrictions are imposed less than 48 hours before kickoff.
UEFA has already reduced the qualifying ties to one leg, except for the Champions League playoff round.
UEFA has also ruled that if one or more players from a team test positive for COVID-19, the match can still go ahead unless the national or local authorities of one or both the clubs involved require the entire squad to be quarantined.
Rescheduling of a match will only be considered if fewer than 13 players from a club's squad are available.