England beat New Zealand in the American city in June in a match that was considered a commercial success and it was hoped would be repeated.
However, the concept met with only a lukewarm response from Australian clubs whose cooperation was essential for the releasing of players.
The National Rugby League has now worked with New Zealand Rugby League to present an alternative, which involves bringing in 2017 World Cup semi-finalists Tonga for games against Australia and the Kiwis.
Tonga will first play the Kangaroos at Mt Smart in Auckland on October 20 with the Kiwis then taking on the Pacific Islanders next June.
NRL chief executive Todd Greenberg said: “This is a fantastic result for all fans of rugby league and the continued growth of the international game.”
NZRL counterpart Greg Peters said: “The Kiwis playing Tonga on home soil is a Test Kiwis fans and the New Zealand Rugby League community have been looking forward to.
“International rugby league is the pinnacle of our game and these Tests are another step towards developing the international calendar.”
The Rugby League International Federation has also welcomed the Tonga fixtures but is concerned the cancellation of the Denver match could impact on the 2025 World Cup, which is due to be held in North America.
RLIF chief executive Nigel Wood said: “The RLIF is excited to see these much-anticipated fixtures taking place and credit is due to all who have worked to get the game on. We hope they will pave the way for an even fuller international programme in 2019.
“Clearly, however, the mid-season game between Tonga and New Zealand removes the possibility of another game in Denver.
“The RLIF will now be seeking further discussions with the promoter to get a full understanding of any potential implications for their bid to host RLWC2025 in the United States.”