The chairman of the Moscow Helsinki Group, Lyudmila Alexeyeva, criticised the absence of serious rivals to a Kremlin-backed candidate.
The group is also seriously critical over enforced censorship and a media law restricting adverse comment.
Referring to media laws concerning election coverage, Alexeyeva said, only "after the election ... will the public be able to read that the election was a farce organised at the highest level".
Another of the group's officials, Tatyana Lokshina, said Chechen voters "had harboured hopes of an end to the military round-ups and of a president other than (Akhmad) Kadyrov" until two key candidates fell out of the race.
Hopes vanished when a local court disqualified businessman Malik Saidullayev on 11 September, just a few hours after Aslambek Aslakhanov, the republic's deputy in the State Duma, withdrew to accept an advisory role offered by Russian President Vladimir Putin.
"Today in Chechnya people are more afraid of Kadyrov's men than of the federal troops," Lokshina said.
"Only after the election... will the public be able to read that the election was a farce organised at the highest level"
The Moscow Helsinki Group
The Kremlin has presented the forthcoming election as part of a political process towards a settlement in Chechnya, arguing the military phase has been won.
Kadyrov, a former mufti who initially backed the separatist insurgency in the early 1990s, has headed the pro-Russian administration in Chechnya since the start of the present conflict almost four years ago.
Russia's brutal war on Chechnya has cost the country up to ten thousand soldiers, and has killed tens of thousands of Chechen civilians.