Final results released by the High Electoral board show the "Yes" campaign received 51.41 percent of the votes, while the "No" votes garnered 48.59 percent.
Final results from Turkey's referendum on changing the system of governance in the country showed 51.4 percent support for the "Yes" vote to approve the sweeping constitutional changes, the High Electoral Board (YSK) said on Thursday.
The results, with 48.59 percent "No" votes, matched the preliminary figures released after polling closed on April 16, the YSK said while explaining the reason for rejecting petitions submitted by three political parties to annul the referendum.
The constitutional changes passed in the referendum will allow Turkey to adopt a presidential system of governance and, its supporters say, will ensure political stability for a country that has experienced multiple unstable coalitions. Opponents claim it will lead to one-man rule.
The changes approved will wholly come into force from November 2019.
After the referendum, concerns were raised by the opposition Republican People's Party (CHP), Peoples' Democracy Party (HDP) and the left-wing Patriotic Party over what they said were flaws in the vote, in particular the acceptance of unstamped ballot papers by the YSK.
But the YSK said the decision was objective, and in line with the principle of equality and impartiality.
"In accordance with the requirements of a democratic society, the right of citizens to participate in governance by voting should be protected against all kinds of obstacles. For this reason, citizens' right to vote is a right that must be protected in cases where it does not violate election security," the YSK said in statement.
The YSK stressed that the mistakes of the ballot box officials who did not stamp the ballot papers in certain locations should not obstruct the people's rights to vote.
On Tuesday, Turkey's Council of State, which handles complaints and appeals against state and public institutions, declined to hear an appeal by the CHP.
The CHP said it would take its appeal to the European Court of Human Rights.
Turkey's president Recep Tayyip Erdogan has said the referendum reflected the will of Turkish voters and the opposition and observer complaints are politically motivated.