Ryan James Henry was at Beerfest on New Year's Eve when he was refused entry, a Launceston Magistrates Court heard. When police stepped in, Henry began acting "bizarrely".

He grabbed hold of a railing and told officers to "call the FBI" because he was going to throw himself into the river.

One of the constables attempted to stop Henry, and that was when he grabbed the officer and pushed them back.

The 19-year-old Launceston bartender pleaded guilty to a charge of assaulting police when he appeared before Magistrate Simon Brown this week.

The court heard after he pushed the officer, Henry resisted arrest and a "violent struggle" ensued in front of other patrons.

During the struggle, a constable injured her leg and later required four sutures.

Lawyer Grant Tucker said his client believed his drink had been spiked, but did not take a blood test to prove this. Mr Tucker described the assault as being at the "lower end of the scale", and said the defendant spent the night of the incident crying and apologising in his cell.

The magistrate agreed pushing the officer was a less serious offence, but said the violent struggle that followed would have been a "very upsetting episode" for those involved and anyone who witnessed it.

Henry was convicted and fined $200, plus court costs of $88.04.

In Tasmania, an average of four police officers are assaulted each week.

In other news:

The latest Tasmania Police Corporate Performance Report revealed 168 assaults on police in the 2018-19 financial year, and 180 the year prior.

The 2018-19 statistics also showed 60 obstruct police, 242 resist police and 318 incidents of police being threatened, intimidated or abused.

In the past four months alone, four serious assaults on police have taken place across the state.

In October, a male officer was kicked in the head and bitten and a female officer was pulled to the ground and kicked in the head during a single incident at Bridgewater.

In November, an officer attempting to intercept a driver with road spikes was hit by the car.

In December, a police officer on motorcycle duty in the South was injured when a driver allegedly reversed his car and ran into him, twice.

In January, an officer was struck by a stolen motorcycle at Clarendon Vale. Police Association of Tasmania president Colin Riley said the rise in serious assaults on police was concerning.

"We are seeing an upward trend in officers on workers compensation claims," he said.

"This is not only detrimental for the officers and their families, but increases strain on the officers who remain in the workplace with the workload not diminishing.

"Minimum safe numbers on first responder shifts is a significant part of the answer here."