Refugee advocates liken it to a prison; it looks like a prison and could become a facility to augment the expensive Risdon facility.

Critics of mandatory sentencing believe Risdon prison will soon fill up once the laws start to bite, just as they have done in other states.

The cost of our justice system, excluding police, is about $124 million a year for the prisons, courts, legal aid and compensation for victims.

It costs about $320 a day to house an inmate at Risdon. Prison numbers are falling, but mandatory sentencing, plus an end to suspended sentences, along with community pressure for tougher punishment, means that Risdon numbers will swell again.

The jail holds 280. Together with women's facilities and the remand centres in Hobart and Launceston the system is stretched at a 410 bed capacity statewide.

If the government wants to avoid embarrassment it will need a circuit breaker.

Pontville is a purpose-built detention centre. For a minimum security facility and replacement for Hayes prison farm, it would avoid the need to build another prison.

In 2005, taxpayers spent $110 million on a new prison plus modifications.

There are no votes in prisons. People want criminals to get jail, but not a five-star hotel. Pontville cost a mere $15 million and can house 350 inmates.

It would save the government a fortune by scrapping Ashley Detention Centre as a minimum security youth facility.

It was always a puzzle why the government closed Hayes prison farm and relocated operations to the confines of Risdon, given the farm's rehabilitation value.

Surely this is where Pontville solves everything. The state could easily acquire it from the Commonwealth.