The nine-member delegation is headed by Hesamuddin Hesam, deputy director of the national directorate of security, the Afghan intelligence agency.
The team includes senior officials from the ministries of defence and interior and the NDS, the sources said. The Afghan officials will begin talks with their Pakistani counterparts tomorrow to share "intelligence" on Rabbani's assassination by a Taliban suicide bomber. The delegation will stay in Pakistan for two days.
The delegation was earlier scheduled to travel to Pakistan in October but Islamabad's objections over the constitution of the panel delayed the visit, the sources said.
Rabbani was killed by a suicide bomber at his residence in Kabul on September 20. The attacker met the former Afghan President in the guise of a Taliban messenger. The Taliban initially claimed responsibility for the murder but later denied reports of their claim.
Afghan President Hamid Karzai had announced that he intended to send members of an inquiry commission to Islamabad to seek "help from Pakistani brothers" in the investigation.
Pakistan agreed to receive the delegation during a trilateral summit in Turkey earlier this month, sources said.
President Asif Ali Zardari and KArzai had met on the sidelines of the summit in Istanbul. Afghanistan has formed an inquiry commission headed by Defence Minister Gen Abdul Rahim Wardak to probe Rabbani's killing.
