UPDATED 11.55AM: A woman with terminal cancer takes the first step in her fight for assisted suicide in the High Court this morning.

OPINION: Rachel Smalley - Assisted suicide back in headlines

Wellington lawyer Lecretia Seales is battling brain cancer, and wants a doctor to be able to help her die before her suffering becomes unbearable.

Medical Association chair Doctor Mark Peterson says doctors are wary of the precedent the case could create.

"With appropriate palliative care, there should be no need for people to request euthanasia or assisted suicide."

Doctors are wary of a potential change in their job description and Dr Peterson says doctors have been helping people die without pain forever, but there's a difference.

"What we wouldn't say is that actually making them die, rather than making them comfortable while they die, is what we do."

Seales is making her case against the Attorney-General but others are arguing they should also be heard. 

The lawyer for Care Alliance, Victoria Casey, says the Attorney-General doesn't have specialist expertise, and those that do need to be involved.

She says the case could have an affect on the whole of society, not just Ms Seales.