Betham steps down after dismal World Cup
Samoa Rugby Union's Fepuleai said more was expected from the team, who exited in the pool stage after losses to Japan, South Africa and Scotland.
He told Radio New Zealand that a review into the campaign was underway but Betham had already decided to leave after three-and-a-half years in the job.
"Stephen has called it a day, I guess, and there will be opportunities there and I think we will go through the proper process in recruitment of a new head coach and so forth," Fepuleai said.
"The position would be advertised internally and externally and we will secure the best person who we think will take us over the next four years to World Cup success."
Samoa not only failed to make the knock-out rounds of this year's tournament but must face a gruelling qualification campaign to make the next one in 2019 after finishing fourth in their group.
Betham complained during the tournament that referees were singling out the Samoans for their physical style of play but the team continued to give away penalties and yellow cards.
They lifted for their final match against Scotland but the island nation's main newspaper the Samoa Observer said the overall campaign was marred by "wrong selections, poor discipline and the absence of leadership".
Agence France-Presse
