Sir Hugh Orde dreads the day a police officer may have to use a gun because less lethal weapons aren't available, he told the Policing Board yesterday.
In a debate over the use of plastic bullets, he told Board members he stood by his decision to approve the weapon for use without a report on how their use may affect different groups.
He said an Equality Impact Assessment would delay availability - and suggested that was one of the reasons Taser stun guns have not been introduced yet.
Sir Hugh said it is important for his officers to have weapons other than firearms to protect themselves and the public.
He said six plastic bullets were fired during UDA riots in Bangor on August 1 because "the situation was without doubt life-threatening to my officers".
He said that was only the second time in two years that plastic bullets had been used, which he said indicated how reluctant his officers were to use them.
"I must protect my officers," Sir Hugh said. "I have an obligation, both moral and professional, to make sure they have the right equipment."
He said the alternative to plastic bullets " would be more lethal".
"I take no pleasure in using them," he said. "But if the alternative is to draw a firearm then we're in a whole new place."
Sir Hugh said he lives in dread of the " appalling situation" where an officer has to use a gun because Tasers or plastic bullets are unavailable.
"I'm sure the Board would have some very searching questions for me then," he added.