About 5.50pm Friday a man  commandeered Toyota ute towing a large boat with what's believed to be a shortened firearm.

The man who covered his face threatened the driver and told him to follow a white ute in front of them. 

The driver did as he was instructed but a short while later jumped out of the moving vehicle,  which came to a stop nearby without incident.

Police said a shot was fired about this time but nobody was injured.  

The offender fled on foot towards Tarleton Street and the driver was assisted by bystanders with police  attending a short time later.

Yesterday the government signalled carjacking would  become a specific crime in Tasmania. 

Carjacking is usually dealt with as an assault or aggravated assault. 

The offender is described as being in his mid 30s, with black messy curly hair and a skinny build with a tattoo on his inner left forearm. 

He was wearing pale blue jeans and a hooded multi-coloured jacket. 

His face was covered with black material.

Police would like to speak with anyone who witnessed the incident. The investigation is ongoing. 

Police can be contacted on 6421 7511.