Thousands of people gathered at a park in northwest Pakistan Monday for a protest at the reopening of NATO supply routes into Afghanistan, which will culminate in a march the following day.

The protesters will spend the night at the park in the city of Peshawar near a highway used by NATO trucks supplying foreign forces in Afghanistan, as part of the demonstration organised by hardline Islamist group Jamaat-e-Islami (JI).

Between 5,000 and 8,000 party activists had reached the site by the evening, according to police, and the protesters would on Tuesday march towards the town of Jamrud in Khyber tribal district, a key supply route.

Pakistan reopened overland routes to NATO convoys crossing into neighbouring Afghanistan on July 3 after closing them in protest at a US air raid that killed 24 Pakistani soldiers in November.

"Supplying (NATO troops) with goods using Pakistani routes is like arming the enemy," Qazi Hussain Ahmad, a senior JI member told the gathering.

"NATO are killing innocent Muslims in Afghanistan."

A JI spokesman said he expected 50,000 protesters at Tuesday's march.

The protest came after thousands of Pakistani Islamists at the weekend rallied at the southwestern border post of Chaman, vowing to stop NATO supplies into Afghanistan.

The protesters had embarked on a 120-kilometre (74-mile) journey from the southwestern city of Quetta on Saturday and reached the town of Chaman late Sunday where they held the rally.

The protesters shouted "Death to America," "No to NATO supply" and "Long Live Mullah Omar" in reference to the Afghan Taliban leader in hiding.

On Sunday, Maulana Samiul Haq, chairman of the Defence of Pakistan group which is a coalition of organisations protesting the reopening of NATO supply routes, said the movement would continue its protests until the convoys stop.

JI is part of the group.

NATO traffic across the border has so far been minimal, with only a few trucks having crossed into Afghanistan since the routes were reopened.

Officials at the port city of Karachi said a dispute about the payment of damages for thousands of containers blockaded for seven months, which has led to sluggish overland supplies, could be resolved this week.