The decision comes as a fresh blow to rugby, with unions suffering a slump in revenues since the pandemic brought professional sport worldwide to a halt.
"Extended travel and quarantine restrictions that apply to numerous countries, and concerns over adequate player preparation time, mean that any sort of cross-border international rugby competition cannot be hosted in July," World Rugby said in a statement.
Ireland and Fiji had been due to visit cash-strapped Australia, New Zealand were to host Wales and Scotland, and England were set to visit Japan in what is a key period for the sport. Scotland and Georgia were also scheduled to tour world champions South Africa.
"All parties, including member unions, international competitions, professional club competitions and international rugby players, will be involved in the continued evaluation of potential contingency options with a view to achieving an aligned calendar for the remainder of the year," World Rugby said.
"All decision-making will be entirely contingent on national government travel, quarantine and health advice and important player welfare and hosting considerations in line with return-to-rugby guidance recently published by World Rugby."
The decision had been widely expected by the southern hemisphere nations, who also have concerns about the four-nation Rugby Championship -- featuring New Zealand, South Africa, Australia and Argentina -- which is due to start in August.
"With so much uncertainty around international travel because of the Covid-19 pandemic, the decision was really taken out of our hands," New Zealand Rugby chief Mark Robinson said.
"From a New Zealand point of view, we are taking a pragmatic approach to the international Test programme."
South Africa Rugby boss Jurie Roux said the Springboks were already evaluating potential contingency options.
"Any solution will have player health, welfare and appropriate return-to-play protocols at heart," Roux said.
New Zealand and Australia are already in talks about a possible Test series later in the year, and Australian Rugby's interim chief executive Rob Clarke said restoring the Ireland and Fiji fixtures remained a possibility.
"This was an outcome we were anticipating, and we are planning accordingly to host the fixtures later in the year, if possible, and will continue to work with World Rugby to identify a new window within the international calendar to stage the matches," he said. (AFP) APAAPA