British High Commissioner Vicki Treadell says Britain would not abuse diplomatic immunity because it is there for a good reason.
"Our position on this is very clear, that you have it for the purpose of representing Britain and doing your job.
"You don't have it to get away with criminality," she told the Herald.
She would not comment on the current case in New Zealand - which does not involve a British diplomat despite TV3 running a picture of a British flag on Monday during an item on the diplomat who fled New Zealand under diplomatic immunity after being charged with sexual assault.
Mrs Treadell said diplomatic immunity allowed diplomats to go about their business on behalf of their government and was particularly useful in countries with poor human rights.
"You could be a diplomat in a country with an appalling human rights record where your job legitimately as a diplomat is to speak out against those human rights abuses."
That was likely to be a country where freedom of expression and a free and open media did not exist.
"So yours will be one of the few voices that can be heard on a subject like that."
The Government could not arrest and imprison you as they might with a local journalist.
"I regret there are some countries that - if anyone commits a criminal offence that they should be accountable for - use diplomatic immunity not to be accountable."
That was not to say their home country would not deal with them.
Mrs Treadell made her comments without knowing where the diplomat at the centre of the latest case in New Zealand came from.
She is due to finish her term at the end of the month and will then become High Commissioner to Malaysia.