It is the first result of a two-year investigation after serious faults were found in the construction of houses, apartment blocks and high-rise buildings, which collapsed in the May 21, 2003 quake in Boumerdes, northern Algeria. The 28 also have to report to a police station every day. They are not yet accused of any crime, but are required to be available at short notice to face possible charges related to the poor construction of public and private buildings.
More than 10,000 people were injured and at least 100,000 were made homeless by the earthquake-prone North African country's worst tremor in more than a decade.
The Boumerdes public prosecutor has interrogated more than 500 people, including 100 architects or construction engineers.
Newspapers and citizens' associations have criticised the slow progress in bringing to justice those suspected of failing to follow regulations when they build in a seismic area.
Authorities have since tightened construction rules.