The group of former Fiji soldiers, in the Bougainville area of Tonu, have been given another week to leave Papua New Guinea.
Last week, the government had said their visas were due to expire today.
The six have been giving military training to supporters of the money scheme manager, Noah Musingku, in an area controlled by Me'ekamui rebels in the south of Bougainville Island.
Bougainville's vice president, Joseph Watawi, says the Fijians' visas expire on December 28, and if they refuse to leave, they will be arrested.
"We do not restrict ourselves to actually consulting with these people to understand and realise that we cannot continue to entertain people that are breaching the laws. They must go."
The Bougainville vice president, Joseph Watawi.
