Tassie diesel bill exceeds $8 million

Backup generators supplying electricity in Tasmania have used $8.4 million worth of diesel in about the first month of use, the state government says.

Taxpayers have spent more than $8.4 million on diesel to run backup generators to keep the lights on during Tasmania's energy supply crisis.

For about a month up to the end of April, the state government made alternative arrangements to meet supply demands because low rainfall impacted the state's hydro-electric scheme while a Bass Strait electricity cable was damaged and inoperable.

"The government has been upfront on the costs of the energy supply plan and the fact they would be considerable, but the cost of doing nothing would be worse," Energy Minister Matthew Groom told parliament on Thursday.