The court is preparing for a deluge of spectators and is considering hiring a larger room to accommodate them.
Last year Green was sentenced to one month in prison under a controversial Swedish law that forbids agitation against certain minorities, including homosexuals.
In a sermon delivered in 2003 the pastor said that homosexuality is a “cancer on the face of society”, and said that it could lead to bestiality and paedophilia. The details came to the attention of the prosecutor when Green himself distributed the text of the sermon to the local media in Borgholm, on the island of Öland.
In the original verdict, the court ruled that certain phrases in his sermon amounted to an attempt to stir up hatred of homosexuals.
But in January the appeal court in Jönköping overturned the verdict and Green was freed, a decision which gay rights groups described as “disturbing”.
In March the state prosecutor announced his decision to appeal against the not guilty verdict.
The case is being billed as a battle between gay rights and freedom of speech.