A woman with a history of drug addiction, a personality disorder and a "lifetime tendency towards intense emotions and rage" has been sentenced to nine years jail for killing another woman whose body she dumped on a Mornington Peninsula beach.

Nicole Boroviak, 44, will be eligible for parole after six years over the manslaughter of Joanne Martell, 43, in a Dromana home in January 2015.

Nicole Boroviak has admitted killing Joanne Martell Credit:Jason South

In the Supreme Court on Friday Justice John Champion described it as a "very traumatic" and "spontaneous" killing and slammed Boroviak for enlisting her son's help to dispose of the body.

She was stoic as her sentence was read out, as she had remained throughout the proceedings.