Tonga's Fire Commissioner has ruled out any malicious activity causing the blaze which destroyed much of Prime Minister 'Akilisi Pohiva's residence.
Lofia Heimuli says his investigation team is about to hand in its final report on Thursday's fire which occurred while Mr Pohiva and his wife were in New Zealand for medical treatment.
Mr Heimuli says there is nothing to indicate the fire was deliberately lit.
"This fire was an accidental fire. No other information that could tell something unusual happened or occurred that caused the fire. The fire was an accidental fire. No other reason."
Mr Heimuli says it could have been started by an electrical fault.