Guidelines on assisted suicide law will be published by the Director of Public Prosecutions this week to clarify when people are likely to be prosecuted.
Keir Starmer QC told the BBC factors that would be considered included whether anyone helping in the suicide stood to gain financially.
He said assisted suicide would remain an offence as the law was unchanged.
The guidelines for England and Wales come after multiple sclerosis sufferer Debbie Purdy won her legal campaign.
The Law Lords accepted earlier this year that Ms Purdy, from Bradford, had a right to know whether her husband Omar Puente would be prosecuted if he helped her to travel abroad to commit suicide.
'Informed choice'
Mr Starmer told BBC One's Andrew Marr Show the basis for the guidelines to be issued on Wednesday.
"What we're doing this week is to clarify when individuals are more likely to be prosecuted or more unlikely to be prosecuted", he said. read more
