The two front runners in Honduras' presidential election are still neck and neck as the vote count enters its fourth day.

With just over 84% of the votes counted, conservative candidate Nasry Asfura - who has the backing of US President Donald Trump - moved ahead of centrist TV presenter Salvador Nasralla, but the difference between the two is minimal at just 0.3 percentage points.

The vote count has been delayed twice by technical outages, which electoral officials called "inexcusable".

The electoral council has urged Hondurans to be patient and police have increased security around the hotel where the votes are being tallied.

Election officials could not contain their anger when the count ground to a halt again for several hours on Wednesday.

The president of the National Electoral Council (CNE), Ana Paola Hall, blamed the private company tasked with tabulating the results for the delay.

She said the firm had carried out maintenance without warning or checking with the CNE.

The stoppage came a day after the portal displaying real-time results had crashed.

The technical problems have further heightened the tension which has beset this election.

The earliest preliminary reports by the CNE released on Monday had shown Nasry Asfura in the lead.

The 67-year-old National Party candidate has the endorsement of President Trump, who has threatened to cut off aid to Honduras if he is not elected.

When the CNE announced later on Monday that Salvador Nasralla, 72, had overtaken Asfura in the count and that only around 500 votes separated the two, Trump accused it of "trying to change" the outcome of the election.

"If they do, there will be hell to pay," the US president said without providing any evidence of any fraud in the Honduras election.

In the early hours of Thursday, the vote count tipped into Asfura's favour again, but the result remains far from certain.

Meanwhile, both Nasralla and Asfura say they remain confident of victory, citing their parties' own vote projections.