The Organization for Security and Cooperation in Europe (OSCE) says there is little evidence of full-fledged campaigning and few opportunities for debate, with state media devoting most air time to praising the authorities.
In a second interim report before the September 28 parliamentary poll, the OSCE also said election officials had failed to provide assurances that observers could witness the vote count.
"The campaign is being conducted in an extremely low-key manner throughout Belarus and few candidate meetings have taken place thus far," the OSCE report said.
It said media coverage "has focused primarily on procedural aspects of the election process," giving voters little chance to become acquainted with candidates or issues.
President Alyaksandr Lukashenka, accused of crushing fundamental rights during 14 years in power, appealed to the West this week to recognize the election and work to improve relations and lift sanctions against the ex-Soviet state.
The rights group said that Belarus's Central Election Commission "has not given its assurances that observers will have meaningful access to the vote count."
No election held in the former Soviet republic since the mid-1990s has been deemed free or fair and the liberal and nationalist opposition, frequently beset by internal rows, was shut out of parliament in the 2004 race.