In a ruling published Thursday, judges of the Special Court for Sierra Leone ordered a subpoena served on Campbell and if necessary to enlist the help of law enforcement agencies wherever she is found to make sure she gets to court.
The appearance of Campbell, as well as of actress Mia Farrow and the model's former agent Carole White, who do not appear to have resisted testifying, will add a touch of glitz to a case already seen as a landmark, the first time a former African head of state has been put on trial by an international court.
Prosecutors complained to the judges that they had tried unsuccessfully to contact Campbell several times since June 2009, when they received information that Taylor had given her a rough diamond as a gift during a celebrity-packed 1997 reception in South Africa hosted by then-President Nelson Mandela.
They said Campbell's testimony would support their contention that Taylor lied when he testified that he never possessed rough diamonds.
"The prosecution has shown that there is at least a good chance that the information to be provided by Ms. Campbell would be of material assistance to its case," said the ruling dated Wednesday.
It cited Campbell's public statements that she "does not want to be involved in the case."
It did not say when the women would be required to appear, but it would not be until the defense finishes calling its witnesses, probably next month.
Taylor is accused of supporting rebels in Sierra Leone's 1991-2002 civil war, which claimed an estimated 500,000 victims of killings, systematic mutilation or other atrocities, with some of the worst crimes committed by child soldiers who were drugged to desensitize them.
His trial is being held in The Hague for fear of renewed violence if hearings were conducted in Sierra Leone. After several false starts, it began in earnest in January 2008. Taylor's own testimony took seven months.
Defense attorneys objected to the request to summon Campbell, arguing that the prosecution had concluded its case 18 months ago and that Campbell's story is irrelevant since she cannot testify to any connection between the diamond and Taylor's alleged involvement with Sierra Leone rebels. The court ruled earlier this week, however, that the prosecution could summon the three women.
Campbell's lawyer, Gideon Benaim, has told the court he would accept a subpoena, if served, according to the ruling.
Farrow already has given a written statement to the court that Campbell told her about the gift, but the judges refused to accept the statement when the prosecution tried to introduce it as evidence last January. Under cross-examination, Taylor said the story was "totally incorrect."