Police are investigating a suspicious overnight fire that extensively damaged part of a two-storey apartment building in Dartmouth, leaving about a dozen tenants without a home.

Fire crews responded to the call on Pinecrest Drive around 3:40 a.m. Sunday morning.

No-one was seriously hurt, but some of the residents were treated for smoke inhalation.

The building sustained heavy smoke and water damage.

Police are in the early stages of their investigation, but say the fire appears to be to be suspicious.

There have been no arrests made yet and the investigation is ongoing.

The Canadian Red Cross is providing six adult tenants with housing, food and clothing.

Volunteers are also helping a seventh adult with necessities as other tenants made their own arrangements.