The trial of Anders Behring Breivik, the man who killed 77 people last July, was temporarily suspended on Tuesday.
As the trial entered its second day, prosecution and defence lawyers asked for one of the four lay judges to be removed.
It emerged that the judge wrote on his Facebook account shortly after the massacres that Breivik deserves the death penalty.
Capital punishment is illegal in Norway, but lawyers said the statement could put the lay judge’s impartiality in doubt.
Breivik is expected to read out a prepared statement later that will last about half an hour.
In it, he will reiterate his belief that his actions were necessary to protect Norway from multiculturalism and Islam.
He admits to be being behind the killings, but pleads not guilty to charges of terrorism and mass murder.