PNG head coach Dior Lowry said they have secured the services of Australian sports psychologist Stephanie Hanrahan.
The secretary of the Fiji Association of Sports and National Olympic Committee, Lorraine Mar, said psychology was key to any athlete’s preparation.
Team Fiji would undergo medical tests to ensure they are mentally prepared, she said.
“Psychology and nutrition, those are fundamental aspects of an athlete’s preparation,” Ms Mar said.
“But those are some things our national federations are only now slowly embracing. Hopefully, more of those sports will adopt those practices.”
PNG aims to take 52 athletes while Fiji is expecting to send a 500-strong contingent to Apia.
New Caledonia and Tahiti have been the most successful countries at the games although PNG topped the medal table when they hosted the event in 2015.