A new migrant caravan of around a thousand Hondurans hit out for the United States border on Wednesday in defiance of threats from US President Donald Trump.

According to the Red Cross "more than 800, almost a thousand," migrants converged late Tuesday on the town of San Pedro Sula before heading north through Guatemala towards Mexico and the US border.

The caravan, which followed a call on social media, took the authorities by surprise after similar appeals since February failed to muster numbers.

Such groups are a target of Trump, who has vowed to tighten migration policy and build a wall to stop them from entering the United States through Mexico.

Among the latest departures were many families with children.

Alexis Perez, 27, said: "We are done with this government. There is no work."

Around half of them crammed aboard a fleet of minibuses, some that would take them to Tecun Uman on the Guatamala-Mexico border for a $51 fee.

Others opted for the shorter and cheaper trip to Agua Caliente, a town on the Honduran border with Guatemala.

Around 300 migrants were left to hike along the road to Guatemala, or catch lifts from passing cars.