A referendum on several constitutional ammendments approved by parliament has given President Idriss Deby the green light to stand for re-election next year.
The government announced on Tuesday night that that the 6 June referendum on constitutional ammendments which included the abolition of a clause limiting the president to two consecutive elected terms, had been approved by 77 percent of those who voted.
This clears the way for Deby, who came to power in a civil war in 1990, to seek a third five-year term in the 2006 presidential election. He won earlier elections in 1996 and 2001.
Opposition leaders, who had called for a boycott of the referendum, denounced the outcome as a sham.
"The results that were published were imaginary and do not reflect reality because the people massively rejected the power of President Deby on the 6 June when there was a massive boycott," said opposition spokesman Ibni Oumar.
But the government was undeterred.
"We did not doubt Deby's victory for one instant," said Mahamat Hissene, the spokesperson and campaign manager for the ruling party.
He said turnout was "more than 70 percent" and the strong "yes" vote reflected resounding support for a continuation of Deby's presidency.
The constitutional ammendments had earlier been approved by parliament, where Deby's Patriotic Salvation Movement (MPS) holds 113 of the 155 seats.
The referendum also rubberstamped proposals to abolish the Senate and replace it with an Economic, Social and Cultural Council, whose members would all be nominated by the president.
Deby, who was in France, did not immediately comment on the referendum result.
The opposition have called for "a day of mourning" in protest at the outcome on the 27 June.
Landlocked Chad is one of the poorest countries in the world with 80 percent living in dire poverty on less than a dollar a day, according to UN figures. The country is currently hosting about 200,000 refugees from the conflict in Sudan's troubled Darfur region.