New Zealand Rugby (NZR) said the move was an effort to protect the brand of the Waikato-based Chiefs, who have played in the Super Rugby competition across Australasia since rugby union turned professional in 1996.
The NRL, which is Australia-based but has one team in the New Zealand city of Auckland, announced the expansion of the league to Papua New Guinea in 2024 with the island nation's Prime Minister James Marape unveiling the name "Chiefs" the following year.
NZR said attempts to engage the Australian Rugby League Commission (ARLC) over the issue had been unsuccessful and it was seeking an interim and final injunction against the use of the name before the Papua New Guinea team is officially launched later this month.
"For 30 years the Chiefs and their players have built an incredibly strong identity that is widely recognised and loved by fans," NZR Chief Executive Steve Lancaster said in a statement on Thursday.
"We have raised our concerns with the ARLC directly and consistently over the last year in attempting to find a resolution. We now have a responsibility to protect the Chiefs brand."
ARLC Executive Chairman Peter V'landys said the complaint was hypocritical given the New South Wales rugby league team had used the "Blues" brand for more than half a century before the Auckland Blues Super Rugby franchise was launched 30 years ago.
"We will defend this vigorously," he said.
"The hypocrisy is mind-blowing, considering the Auckland Blues in 1996 used the NSW Blues name without any consultation or approval.
"Rugby union is obviously feeling threatened by rugby league in New Zealand, with sell-outs at most rugby league games."
Rugby league split from rugby union in the late 19th century in a dispute about amateurism. While union is the more popular game globally, league rules the roost on Australia's eastern seaboard and has been making great strides in New Zealand.
Papua New Guinea is the only country in the world where rugby league is the most popular sport.
The new team, which has already signed a slew of top NRL players ahead of its first season in 2028, will be backed by hundreds of millions of dollars in funding from the Australian government, which is looking to shore up its influence in the Pacific Islands.
"We want to be absolutely clear, this is not about rugby league's growth in the Pacific," Lancaster said.
"We welcome the development of the Pacific region through sport and the passion that the people of Papua New Guinea have for both rugby and rugby league."
