New Delhi: Left-wing candidate Andres Manuel Lopez Obrador of the National Regeneration Movement has won the presidential elections in Mexico, according to the country's electoral body.

Lopez Obrador called it a "historic day" after the National Electoral Institute (INE) attributed him at least 53 per cent of the votes in a quick count of a sample of 7,700 ballots, Efe news reported.

His closest rivals admitted defeat and congratulated Lopez Obrador on his victory.

"I express my respect to those who voted for other candidates and parties, and also for the three presidential candidates representing the different organizations that have recognized our triumph and victory today,"Obrador told a crowd of jubilant supporters at an event in Mexico City late Sunday (local time).

"I call all Mexicans for reconciliation and to put best interests above personal interests, however legitimate," said Lopez Obrador, who is set to assume office on December 1.

The silver-haired 64-year-old left-wing nationalist promised profound changes in the country during his mandate and assured he would work to establish an "authentic democracy".

He vowed to crack down on corruption through fiscal and financial discipline, and promised intellectual and business freedom.

Lopez Obrador also said he would seek "friendship and co-operation" with the US. Mexico's relations with Washington have been strained since the election of President Donald Trump who has strongly criticised the country over trade and migration.

However, Trump took to Twitter to congratulate Lopez Obrador "on becoming the next President of Mexico".

Lopez Obrador's nearest rival, Ricardo Anaya of the conservative National Action Party, was placed second with 22 per cent of the vote, followed by Jose Antonio Meade of the ruling Institutional Revolutionary Party with around 16 per cent of the vote, and the independent Jaime Rodriguez with 5.5 per cent.

The opposition had admitted defeat after the exit polls had indicated landslide victory for Lopez Obrador shortly after voting ended.

The ruling party's candidate Meade said at a public gathering that the voting tendencies did not favour him. "At this moment, we will have to recognize that according to the trends, it was Andres Manuel Lopez Obrador who obtained the majority.

"He will have the responsibility of leading the executive power and, for the good of Mexico, I wish him the greatest success," Meade said to his supporters.

Meade, a technocrat who has held several Cabinet posts, including Finance Minister, said Lopez Obrador will take over the helms of a country that has seen growth, improved employment outlook, and progress in fighting extreme poverty.