In the capital Bogota, demonstrators blocked major roads and set fire to makeshift barricades to support Petro and his stalled agenda.

“We all need to get out onto the streets, all the youth, to show we want labour reforms to pass,” 25-year-old pharmacist Karen Calderon told AFP.

Petro is the first leftist leader in Colombia’s history and was elected with absolute majority support during a 2022 presidential runoff.

Since then, however, he has struggled to translate campaign victories into legislative success.

Several key election promises have yet to be realised as he enters his last year in office, and his coalition cabinet has been riven by infighting.

Facing fierce opposition from lawmakers to sweeping overhauls of labor and healthcare laws, Petro took the unusual step of backing a two-day general strike on Wednesday and Thursday.

The one-time guerrilla is demanding a popular referendum to ask voters whether they want more overtime pay and a range of other measures.

“There is the right to a popular consultation,” the president emphasised on the social network X.

The strike caused widespread disruptions across several cities but was not universally observed.

Bogota’s public transport authority said 850,000 residents were affected by blockades at major bus stations.

Petro must leave office next year, but he is trying to rally his supporters ahead of May elections.

His government has warned that if Congress refuses to pass the reforms, it will declare a referendum by decree – a move that is likely to face stiff legal challenges.