Archaeologists in Tasmania have found more than 300 convict-era artefacts under the floorboards of a 180-year-old chapel.

The discovery at Hobart's historic Penitentiary Chapel includes coins, clay pipes, home-made wooden gambling tokens, a writing slate and bones.

Archaeologist David Roe says it is particularly exciting because the artefacts are very personal items belonging to the prisoners.

"The gaming tokens for example, we will be looking at the patterns of those compared to the ones from Port Arthur from other sites in Tasmania, from Hyde Park Barracks and hopefully from the UK, which is essentially part of the same system," he said.

"This is our fourth day now, we had a colleague down from the University of Sydney who works on convict sites in New South Wales and Western Australia, and his opinion was that this is one of the best under floor deposits he had ever seen, so they are really uncommon and I think once word gets out people are going to be really excited about this."

Archaeologists say the items provide new insight into the convict experience.