The centre-left Arevalo was elected in a landslide win in August, but since then Attorney-General Consuelo Porras has intensified efforts to disqualify his anti-graft Movimiento Semilla party and ordered raids on the electoral authority's offices, seizing ballots.
"We're going to paralyse the country indefinitely. We demand the resignation of the prosecutor, Consuelo Porras," said protester Luis Pacheco, head of 48 Cantones, a large Indigenous organisation.
Pacheco spoke on Thursday outside Porras' offices in Guatemala City, where other groups have been camping out since Monday, waving Guatemalan flags and hoisting signs demanding an end to corruption.
Another sign read: "Get out, coup plotters."
The prosecutor's office has defended what it describes as lawful actions to investigate Semilla over alleged registration issues and the need to secure evidence via raids.
Arevalo, a previously little-known lawmaker who struck a cord with his campaign pledge to tackle corruption, is fighting a bitter post-election battle with entrenched foes ahead of January's scheduled inauguration.
After he secured unexpectedly strong support in June's first-round vote, Porras asked a judge to disqualify Semilla, alleging the six-year-old registration flaws.
Her office's raids have prompted international criticism while also stoking popular anger. A wide range of protesters, including Indigenous people, rural farmers, and teacher and student groups have taken to the streets to demand the resignations of Porras and one of her top prosecutors, Rafael Curruchiche.
Both have been accused of corruption by the US government.
President Alejandro Giammattei, who in August promised an orderly transition, nominated Porras to her present term as attorney general, and has mostly remained silent on the investigations and raids.
On Wednesday, Giammattei's government said it was restarting transition talks with Arevalo's team.
