While international attention focuses on the disruption caused by violence blamed on the Taliban and allies including al-Qaida, other local commanders are resorting to threats and harassment to sway votes in their favour, the private, New York-based lobby group said in a report on Tuesday.
"The warlords are still calling the shots," the group's Afghan researcher John Sifton said, referring to regional commanders who have resisted efforts by interim President Hamid Karzai to disarm them.
"It's been almost three years since the fall of the Taliban, and there was supposed to be progress towards democratisation, disarmament and elections. But the reality today is the democratic process has only entrenched the warlords," he added.
With no guarantee security will improve between the presidential election on 9 October and parliamentary elections in April, the latter could be marred by "widespread political repression and violence", the group said in its report.
Karzai has had only partial success in reining in commanders who have clashed with rival factions and have turned down offers to leave their strongholds to join the central government.
Karzai, who enjoys international support, is widely expected to win the presidential vote, but there is concern among Western diplomats that the more complex parliamentary elections could be manipulated by commanders and their political parties.
"The refrain of this election not being perfect is being used as a shield for significant failures in election preparations"
Human Rights Watch
"Human Rights Watch urges President Karzai and the Afghan government to continue to step up efforts to sideline abusive commanders and refrain from deal-making that would further entrench warlord rule," the report said.
Regional commanders were instrumental in helping the US military defeat the Taliban in late 2001. Some have seen their powers reduced. Others continue to operate alongside US-led forces in Afghanistan, hunting fighters.
Human Rights Watch also highlighted the absence of formal international observer missions for the presidential poll due to concerns for observers' safety: "The refrain of this election not being perfect is being used as a shield for significant failures in election preparations," Sifton said.