Colombia voters reject FARC peace plan: Near-full results

They voted 50.23% to 49.76% against the accord, with more than 99% of the votes counted, according to official results.

Colombian voters have rejected a peace deal with communist Revolutionary Armed Forces of Colombia (FARC) rebels, near-complete referendum results indicated, unexpectedly blasting away what the government hoped would be a historic end to the 52-year conflict.

Reversing the trend of earlier opinion polls, voters appeared to have narrowly defied the government's pleas for a new era of peace in the South American country.

They voted 50.23 per cent to 49.76 per cent against the accord, with more than 99 per cent of the votes counted, according to official results published online by electoral authorities.

Supporters of the accord had expected it to effectively end what is seen as the last major armed conflict in the Western hemisphere.

The war has killed hundreds of thousands of people and displaced millions.

But Sunday evening's results pointed to a crashing defeat for President Juan Manuel Santos and the accord that he signed on September 26 with the FARC.

Santos's government had said it had no Plan B if voters rejected the accord, which stipulated that the agreement must be ratified by Colombians in a referendum in order to come into force.

Opinion surveys by pollsters Datexco and Ipsos Napoleon Franco, published on September 26, indicated the 'Yes' vote would win by a margin of around 20 per cent.