NZR said it was forced into legal action after being unable to "engage with the ARLC constructively" over the past 12 months to work towards a resolution.
The NRL franchise is set to officially unveil their logo and jersey at a launch in PNG later this month, which co-incides with a Rugby League World Cup match in Port Moresby on Saturday October 24.
The rugby governing body is seeking both an interim and final injunction to stop the Australian Rugby League Commission (ARLC) from using the names "PNG Chiefs", "Chiefs", or any other similar names in New Zealand.
The NZR said it had owned both the trademark rights for the word Chiefs and the Chiefs logo since 1998, used by the Hamilton-based team in Super Rugby. It also said it held trademark protection for the franchise's logo in Australia.
NZR said it raised concerns with the ARLC when the expansion side's name was confirmed in October 2025 ahead of of their 2028 start in the NRL but with no "positive outcome" had to take legal steps.
"For 30 years the Chiefs and their players have built an incredibly strong identity that is widely recognised and loved by fans," NZR CEO Steve Lancaster said in a statement.
"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.
"We want to be absolutely clear, this is not about rugby league's growth in the Pacific. 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."
NZ Rugby said using "Chiefs" for the expansion team would cause "significant confusion and damage", as both brands would be playing and trading in the same markets.
The organisation claimed the view was shared by IP Australia, the Australian Government agency that administers intellectual property (IP) rights, which warned of a "real and tangible danger of confusion" when ARLC applied for trademark protection for "PNG Chiefs".
