B.C.'s Attorney General says a decision on whether to try serial killer Robert Pickton on 20 more murder charges has received mixed reaction from families of the victims.

Wally Oppal says Pickton will not face trial on a further 20 counts of murder unless the six murder convictions from his first trial are overturned on appeal.

But if the B.C. Court of Appeal rejects Pickton's appeal on the six counts of second-degree murder, then plans for a trial on the remaining 20 murders will be dropped.

Oppal says Canada has no provision in law for consecutive life sentences, and Pickton's sentence is already the maximum possible.

Lori-Ann Ellis, whose sister-in-law Carrie Ellis is among the 20 outstanding cases, wants the trial to go ahead so her family has it's day in court.

Lilliane Beaudoin, whose sister Diane Rock is also among the women, was outraged saying she'll actually never know who committed the crime.

Pickton was sentenced to life in prison with a minimum of 25 years before he can apply for parole on six counts of second-degree murder last December.

It followed one of the most complex and expensive investigations and trials in Canadian history.