"Clubs and schools would not have adequate time from midnight Friday to prepare to host games within government guidelines, so we will wait another week and hopefully, rugby can play its part in helping the country stamp out this outbreak.
"We share the disappointment of players, fans and other stakeholders and know it's especially tough for the secondary schools involved in the Top 4 tournament, which provides such a great finale to the first XV season."
The Government plans to review alert levels on Friday, August 27, and Lancaster said NZR would wait until then to make any decisions on rescheduling the latest round of Bunnings NPC, FPC and Heartland Championship matches.
"Everyone wants to be able to play the full schedule and that remains our goal," he said.
"No decisions have been made, so we will pause and see what the Government says on Friday and make some calls from there."
The latest delays mean the start of the Bunnings Warehouse Heartland Championship is now two weeks behind schedule, while the Bunnings NPC has completed two rounds and the FPC presented by Bunnings six and seven rounds in the Championship and Premiership divisions respectively.