The Northern Ireland Chief Constable, Mr Hugh Orde, has warned that some PSNI officers want him to fail.
He told politicians in the United States on Wednesday night that the British government needed to give him more support.
"I currently get more support from the United States of America for this initiative than I do from my own government or from the Northern Ireland Office," he said.
He added that with up to 900 officers still needed on the streets, and with the Police Service of Northern Ireland facing mounting financial pressures, not all his opponents were outside the force.
"There are people who want me to fail. Some of those people are within my organisation," he told the US National Committee on Foreign Policy.
Mr Orde took over from Sir Ronnie Flanagan last September.
However his decentralisation policy and quick-fire demands for change at all levels, including axing the police band, have not gone down well with some members of the force.
He still has the backing of the Policing Board, as well as of the British and Irish governments.
His admission that he does not have 100 per cent support among his own ranks, made in New York, has shocked those who are standing by him as he reorganises the police service by reducing sick-leave levels and getting every available officer out on patrol.
An Ulster Unionist member of the Policing Board, Mr Fred Cobain, said: "If we are going to have a new start to policing, everyone needs to be swimming in the same direction. Undermining the Chief Constable is undermining the police service."
Sinn Féin is still boycotting the 19-member Policing Board, which holds Mr Orde to account, claiming it is not powerful enough.
London and Dublin are pushing republicans to endorse the new policing arrangements - the Chief Constable has said such a move would wipe out his recruitment problems overnight.
He warned however that there could be a dangerous price to pay.
"If, for example, the Provisional IRA agree to stand down, if Sinn Féin join the Policing Board, where does that take the dissident threat?
"Quite frankly, it probably increases the dissident threat short term until we can deal with it, because many people who are not happy will leap across that divide and become dissidents rather than Provisionals."
Mr Orde also voiced frustration that the Police Service of Northern Ireland still did not have a proper training college for new recruits. The former Deputy Assistant Commissioner under Sir John Stevens at the Metropolitan Police, vowed: "I am working on it and we will have one before I leave Northern Ireland."
He told members of the US committee that despite the difficulties, there had been major police successes over the last 12 months.
Officers arrested 236 people for terrorist crimes and charged 85 with serious offences.
Even though 12 murders were committed last year, that was down from 18 in 2001.
"It compares very favourably with 1972, when there were nearly 400 deaths due to terrorist-related crime," he said, "so we need to remember where we have come from."
In his speech, Mr Orde also disclosed that more troops were on the streets of the North than at any time over the past five years to combat the loyalist paramilitaries involved in a deadly internal feud.
"I have dedicated squads targeting both Johnny Adair and enemies," the Chief Constable said.
He also warned that the warring loyalists would soon turn their guns once again against Catholics.
"They lack political leadership, I don't think they understand political leadership," he said. "They will resort to what they do best, which is more random and disorganised violence against the Catholic community."