A man who was raped by a relative at the age of 7 says the Government will have "blood on its hands" if it goes ahead with proposed new rules for sexual abuse counselling.

The Aucklander, now a 26-year-old professional, says he would not be alive today if the new rules were in place.

The rules, due to be implemented from October 12, state the Accident Compensation Corporation will pay for counselling only if victims of sexual abuse are diagnosed with a mental injury under the US Diagnostic and Statistical Manual Version 4 (DSM-IV).

Dr Kim McGregor of the National Network Ending Sexual Violence Together said many counsellors were ethically opposed to using a psychiatric diagnosis for sexual violence and would refuse to do ACC work under the new rules.

But the man, who sought ACC-funded counselling for his childhood abuse when he was a student aged 20, said he would not have survived without the counselling.

"I am absolutely certain that, without the help of a counsellor, the pain and disability that I experienced due to the abuse I suffered as a child would have driven me to suicide. I would not be here today.

"At the time when I went to see my counsellor, I barely had the confidence or strength to tell him about the existence of the abuse," he said.

"If my counsellor had told me I needed to see ACC's shrink three times and be diagnosed with a mental condition before I could go to counselling, I would never have gone back."

The man said many other abuse survivors would not let themselves be "diagnosed as crazy" to get counselling.

In an open letter to ACC chief executive Jan White, he said: "When people start committing suicide as a result of ACC's new policy, the blood will be on your hands."

Figures obtained by Labour ACC spokeswoman Lynne Pillay show ACC has already tightened controls over sexual abuse counselling before the formal policy change next month.

In Auckland, claims for counselling still waiting for a decision escalated from fewer than four last December to 103 by August 20, while the approval rate for claims decided on dropped from 50 per cent in December to 25 per cent in July.

ACC senior medical adviser Dr Peter Jansen said the trends reflected partly an increase in the number of claims from 520 a month last year to 650-700 a month since March, and partly "greater adherence to the existing legislation".

"We have always required a mental health diagnosis. We have been inconsistent in the past in adhering to what the legislation says," he said.

"We do not cover an event. We provide cover for an injury. In the case of a sensitive claim, the wording of the legislation is 'a significant mental injury caused by that event'," Dr Jansen said.

"The 'mental injury' definition is 'a significant cognitive, behavioural or emotional dysfunction', and the way the legislation is framed, and the way court decisions have followed from that, points to the need to have a DSM-IV diagnosis."

He said sexual abuse victims who did not have a DSM-IV mental illness could still go to rape crisis agencies.

"There are a range of agencies that deal with that. ACC does contribute some funding towards those types of services," he said.

But Dr McGregor said ACC had cancelled its $350,000 a year funding for the Auckland Sexual Abuse Help Foundation from the end of next month and funding for other agencies was "not common".

"This sector is dying through two decades of underfunding," she said.

"Rape Prevention Education [in Auckland] is the only agency in the country with a core business to work on preventing sexual violence. Most others stopped prevention years ago because they were struggling to provide crisis support."

Dr McGregor said a taskforce's report was due to be considered by the Cabinet in the next week or two and would be released a few weeks later.