According to the Tonga Police Act 2010, the King in Privy Council is the only person who has the power to appoint or terminate the commissioner's contract. The Act also spells out that the appointment of a police commissioner cannot be terminated except for physical or mental incapacity, neglect of duty or misconduct.
In March, about 150 officers launched two petitions seeking to have Mr Kelley removed and replaced by a Tongan.
The second petition expressed concern at the way Mr Kelley's reforms had affected the long-standing and traditional procedures of local police, stuff.co.nz reported.
It also made personal claims, including a case where Mr Kelley allegedly ordered a police vehicle be made available for his daughter's use when she was in Tonga.
In the earlier petition, signed by 200 officers, Mr Kelley was accused of favouritism in appointment making.
Mr Kelley responded to that with a formal statement saying that he had arrived in Tonga in September 2008 under the brief to initiate reform with the help of the governments of Tonga, New Zealand and Australia.
"Those reforms have included an emphasis on transparency, accountability, re-development and institutional strengthening," he said.
"Change may be at the 'heart' of these perceived grievances, change to merit based promotion, change to a new Police Act and change in the way in which we manage disciplinary proceedings.
"I am confident that the changes we have put in place are responsible, appropriate and in line with modernisation of a police service."
- NZPA