The Health Minister says he has reservations about setting up a National Cancer Agency.

Blair Vining, who has terminal cancer, and his wife Melissa have been campaigning for one to be set up.

They've collected more than 100,000 signatures on a petition calling for the agency.

David Clark told Mike Yardley the ministry is in contact with all other parts of the health care system and can produce a combined approach.

"One of the downsides of looking at an agency is having a separate organisation that's not as well connected to Central Government and not able to be as directed. There are trade-offs through that, and we've worked through those options very carefully."

He also defended a decision not to set a THC limit on medicinal cannabis, the substance is what gives users a high.

People have a month to have their say on the proposed rules about medicinal cannabis, which were released yesterday by the Ministry of Health. 

Clark says the proposals have been put forward by medical experts.

"We'll see whether those other experts out there and the users and everyone else think that that's the right approach."

• Family fighting for cancer care agency disheartened by ministerial meeting