* Ivory Coast votes in tense presidential election
* Incumbent President Ouattara seeking a controversial third term
* Polls open at 0800 GMT on Saturday
By Aaron Ross, Ange Aboa and Loucoumane Coulibaly
ABIDJAN, Oct 31 (Reuters) - Ivory Coast goes to the polls on Saturday as President Alassane Ouattara seeks a third term in an election two rival candidates have urged their supporters to boycott.
Thirty people have died in violence in the lead-up to the election, which is seen as a test of stability in the world's top cocoa producer and one of Africa's fastest-growing economies.
The street clashes have brought back memories of the 2010 vote that Ouattara won but which unleashed a brief civil war that killed 3,000 people when his predecessor Laurent Gbagbo refused to step down.
The recent violence has pitted the 78-year-old president's supporters against those of his opponents, who say he is breaking the law by running again because the constitution limits presidents to two terms, and is jeopardising the country's hard-earned economic gains.
Ouattara says he can run again under a new constitution approved in 2016, and is doing so only because his handpicked successor died unexpectedly in July.
Critics say his candidacy is a fresh blow to West African democracy following Mali's military coup in August and Guinea President Alpha Conde's successful third-term bid this month.
His two main rivals, former president Henri Konan Bedie and former prime minister Pascal Affi N'Guessan, have called for an election boycott. Affi N'Guessan has told supporters to blockade polling places.
The likely result is a Ouattara victory though not necessarily a peaceful one.
"You have to go vote and you have to protect the polling stations against those who want to create trouble," he told thousands at his final campaign rally in the commercial capital Abidjan on Thursday.
"Ivory Coast wants peace. We don't accept disorder."
The government said it would deploy 35,000 soldiers and police officers on election day.
In Abidjan's Yopougon neighbourhood, an opposition stronghold, weary residents said they would simply stay at home.
"This election won't take place under good conditions... people are scared," said Hube Kondo, 42.
(Editing by Edward McAllister and Emelia Sithole-Matarise)