* Court to hear if accusations can lead to full trial
* Gbagbo lawyers accuse court of victor's justice
* Prosecutor promises Gbagbo will answer for actions (Adds prosecutor quotes, Gbagbo behaviour in court)
By Thomas Escritt
THE HAGUE, Feb 19 (Reuters) - Former Ivory Coast leader Laurent Gbagbo sat motionless as the International Criminal Court's prosecutor accused him on Tuesday of plunging his country into chaos in a bid to hold power after losing 2010 polls.
Gbagbo, 67, is the only ex-head of state to appear in the Court, whose credibility is at stake after a string of collapsed cases. The tribunal was holding a hearing to establish whether he will stand full trial for crimes against humanity for allegedly ordering his forces to commit mass murder and rape.
"What should have been a moment of national unity, the first presidential elections in 10 years in Cote d'Ivoire, descended into chaos and unspeakable violence," said Fatou Bensouda, the prosecutor, using the country's French name.
Underlining the tensions which still plague the West African country, Dutch police on horseback held back some 300 Gbagbo supporters protesting outside the court building to demand that the charges that he directed mass killings and rape be dropped.
"He's not a dictator," said one supporter who called himself Babadwe. "Gbagbo loves his people and his people love him. Have you ever heard of a president who kills his people and then has his people love him?"
His lawyers accuse the court of political bias in favour of his successor, Alassane Ouattara, a former IMF official who has sought to kickstart the economy of the world's top cocoa grower and of the country that was once West Africa's commercial hub.
Gbagbo, a 67-year-old former history professor, was dressed in a sober business suit. Though he is not due to speak until next week, he watched proceedings from a seat at the back of the court. He looked relaxed and at one point broke into a broad grin when he spotted familiar faces in the public gallery.
The sessions have been spread over several days to take account of his health, which his lawyers say was weakened by months of detention in Ivory Coast before his transfer to the Hague court in November 2011.
Ouattara's government said it would have been impossible to have held a fair trial of Gbagbo in Ivory Coast and feared it could have triggered fresh bouts of violence, an argument which Gbagbo's lawyers reject.
"If the chamber declares this case admissible there would be a risk of saying this will be a court of convenience, pliant to the will of local leaders as it is today with Ivory Coast," said Dov Jacobs, a lawyer for Gbagbo.
The hearing is crucial for the Court's own prosecutors, who will seek to convince judges that Gbagbo has a case to answer after a string of high-profile failures.
They must prove that Gbagbo ordered his forces to commit murders, rapes and other human rights violations during a four-month civil war in which some 3,000 people died and a million were uprooted from their homes.
Late last year Congolese warlord Mathieu Ngudjolo Chui was acquitted in the court's second ever verdict, and prosecutors have failed to make charges stick against four other African suspects.
Bensouda said the court would bring justice to the victims of the post-election violence in Ivory Coast and hence deter future attempts by politicians to resort to violence.
"This is not about who won or who lost the elections," she said. "We are here to send a clear message to those ... who try to take power or hold on to it by using violence and brutality: from now on they will answer for their actions."
Gbagbo says he was leading government resistance against what he describes as Ouattara's foreign-backed northern rebellion. Ouattara saw himself as the champion of excluded northerners who suffered under Gbagbo's southern government.
The conflict came to an end only after Gbagbo was arrested by forces loyal to Ouattara, with the help of French troops, prompting Gbagbo's supporters to argue that he is the victim of post-colonial meddling.
Prosecutors have also issued an arrest warrant for Gbagbo's wife Simone, but Ivory Coast has not surrendered her to the ICC's custody.
A close Gbagbo ally, the leader of the Young Patriots youth movement Charles Ble Goude, was arrested last month in Ghana and was immediately extradited to face trial in Ivory Coast.
Gbagbo supporters and human rights groups have complained that abuses carry out by pro-Ouattara forces during the conflict have yet to be punished, arguing that this is holding back efforts to reconcile southerners and northerners.
Many Ivorians want to draw a line over the whole conflict.
"I think that the youth need to understand that Gbagbo has had his day and it's over now," said Norbert Toualy, a pensioner in the commercial capital Abidjan. "He can come back after his trial, but he's no longer going to be president." (Additional reporting by Ange Aboa and Joe Bavier in Abidjan and Mark John in the Hague; editing by Mark John)