Several flights have been cancelled this week and passengers re-routed after the lease expired on a Boeing 737-800 aircraft at the end of March.
The airline said efforts to secure a suitable replacement aircraft started as a result of the global grounding of MAX 8 aircraft in the first half of March, triggered by the air crash in Ethiopia.
It said there is a huge shortage of narrow-body aircraft as airlines scramble to consolidate their schedules using existing fleets and short-term leases.
Samoa Airways said a team from Malindo Air has just completed an audit of its operations and it is working with civil aviation authorities in Australia, New Zealand, Malaysia and Samoa to get safety and regulatory approvals.
It said the national carrier and Malindo Air anticipated the clearances will come through towards the end of this week.
Samoa Airways said it had been able to contact most of the customers affected and set up alternative flight arrangements.