The New Zealand-based team touched down in Tamworth on Sunday, with uncertainty still surrounding how long they will be away from home.
At this stage, they have committed to remaining in Australia until at least April 4, but whether they can host games in Auckland from round five will depend on COVID-19 quarantine measures.
Monday's return to pre-season training will mark the first time several players have seen each other since the end of last season.
Pre-Christmas training was done in two separate groups, with those who wanted to remain in Australia at the end of the 2020 season able to train there.
The Warriors won just three of their first 11 games last year in a season full of uncertainty, no home games and players leaving early, before rebounding late.
But while there is again little clarity on whether they will be able to return to Auckland from May, chief executive Cameron George says it will not hurt the team on the field in 2021.
"Starting the 2021 season in Australia isn't what we wanted to do but it's what we have to do," George wrote in an open letter to fans.
"This time around, however, we're prepared for what lies ahead and accept that the future still remains very uncertain.
"We want all our fans to know that despite the adversity we are again dealing with, we're committed to fronting up and having a crack.
"We do not want anyone feeling sorry for us and, while it's not a perfect situation, it's what we've been tasked to do."
The Warriors will "host" Gold Coast and Newcastle at Central Coast Stadium in the opening two rounds of the season, before being away in rounds three and four.
It is hoped their round-five clash with Manly will be able to go ahead at Mt Smart Stadium, in what would be one of the most anticipated NRL matches there in memory.
The Warriors have not hosted a game in New Zealand since round 24 of the 2019 season on August 30.
They hosted "home" games in round two and three of the 2020 season on the Gold Coast, prior to the coronavirus break.