Mr Hazlehurst said Brady's latest protest began after he was told that an advocate previously based at the hospital would no longer be allowed to see him.
Brady, who is 63, is a patient at Ashworth Hospital on Merseyside.
He has been been on hunger strike for more than 500 days, and during that time has been fed liquid food through a plastic tube.
The process takes between four and five hours every day.
Following a dispute with staff at the hospital, Brady said on Monday that he was no longer prepared to accept the tube, which is passed through his nose and down his throat. He said that from now on he would take only liquids.
His lawyer, Alan Hazlehurst, said Brady will be at risk if he is no longer receiving his daily intake of liquid food.
Health risk
"If you reduce your level of intake to simply some liquids, without appropriate nutrients, clearly you are going to damage your health," said Mr Hazlehurst.
"If Mr Brady is taking only water or coffee he will not be getting what is required to sustain him."
Mr Hazlehurst said Brady's latest protest began after he was told that an advocate previously based at the hospital would no longer be allowed to see him.
Then, according to Brady, a letter from the advocacy service was not delivered to him.
Infuriated
"All this has infuriated him, and it has triggered a situation in which he is no longer prepared to accept his feeding tube," said Mr Hazlehurst.
"I think he encapsulates a situation in which a number of patients feel they are treated in a way that does not take their rights into account. They feel decisions are made only on security grounds."
Last year, Brady went to the High Court in Liverpool to challenge the power of the hospital to feed him against his wishes, saying he wanted to be allowed to starve himself to death.
He lost the case, but his lawyer says he is ready to go back to court if efforts are now made to feed his client by force, using the plastic tube.
Legal challenge
"This is a fresh situation and Mr Brady would have a right to challenge any decision to feed him forcibly, and to ask whether it is in his best interests for the hospital to do so."
In a letter to the BBC, written shortly before this latest dispute, Brady says his attitude towards the hospital is the same as when he began his hunger strike on 30 September, 1999.
"I have made no demands, no requests, no negotiations, other than the wish to die," he says.
"My resolve remains the same. I would rather be dead than exist under these conditions."
A spokeswoman at Ashworth Hospital said she could not comment on Brady's treatment because of patient confidentiality, but his condition remained unchanged and he was comfortable.