A man accused of hitting two senior police constables at a random breath testing site, leaving them with critical injuries, was looking at his phone for up to 20 seconds at the time, a Sydney court has heard.

Jakob Thornton, 22, allegedly struck the officers as they were setting up at Leameah last night, with one of the officers needing his foot amputated.

Mr Thornton has admitted to using a mobile phone in the lead up to the crash.

The court heard this is the second time Mr Thornton has been charged with using a phone while driving, and he has had his license suspended four times.

Mr Thornton's lawyer Carl Minette applied for bail for the Rouse Hill man, telling the magistrate his client is looking at a full-time custodial sentence if convicted.

"He has a job, a girlfriend, he lives with his mum, brother and sister, he has no health, alcohol or drug issues," he said.

"He was unaware that one of the officers had to have a foot amputated and he was really shocked when he heard that."

The defence pointed out police have already confiscated Mr Thornton's licence, but the prosecutor Leesa McEvoy opposed bail, describing the strength of the case as "nothing short of solid".

"The facts are horrific. This young man hit two officers when he was driving at 60 kilometres per hour," she said.

"By his own admission, he was looking at the phone for 10 to 20 seconds and he collected them.

"I mean it when I say there are no clear winners in this case.

"I don't think anything can be done to make this young man feel better but there needs to be a message sent to the community."

The 22-year-old driver allegedly trapped two police officers between his car and a police car. ( ABC )

In refusing bail, the magistrate said there was a risk Mr Thornton will get behind the wheel again, especially if he lost his job.

"The concern I have is he's got a prior record for driving while using a phone and he has four prior suspensions of his P2 licence," he said.

Mr Thornton was uninjured in the crash and has been charged with multiple dangerous and negligent driving offences, as well as causing bodily harm by misconduct and using a mobile phone when not permitted.

He will remain in custody until his next court appearance at Campbelltown on Wednesday.

Officers were trapped between vehicles



Both officers remain at Liverpool Hospital, one officer is in a critical but stable condition, the other is in a stable condition.

Police Commissioner Mick Fuller visited the two constables in hospital and said one of the officers had to have part of his leg amputated.

"We will allege [the man] on his mobile phone has driven into the back of a police vehicle, striking and trapping two police officers between that vehicle," Commissioner Fuller said.

"One of the officers sustained a serious fracture.

"The other officer ... lucky not to have lost his life, has unfortunately had part of one of his legs amputated as a result of those injuries."

Commissioner Fuller said the man who had lost part of his leg would have his full support going forward in the force.

"[This incident] is aggravated by the fact two officers were out on a Friday night trying to protect the community from this type of driving behaviour.

"We talk ad nauseum about traffic safety and some days you have to wonder what we have to do."

Opposition Leader Luke Foley is calling on the NSW Government to introduce "slow down move over laws".

He says similar laws that require drivers to slow down to 40 kilometres an hour when passing emergency vehicles are already in place in other states.

Two other police injured at another RBT

In a separate incident on the northern beaches, a man allegedly refused a breath test, resisted arrest and left two other officers with injuries.

The driver was placed under arrest after refusing to supply a sample at Belrose, but while being escorted to the RBT bus he swore, became argumentative and violently resisted arrest.

Two male senior constables suffered injuries, one a fractured wrist, the other a groin injury after he was allegedly kicked by the man.

The 25-year-old has been charged with a range of offences including assaulting police and causing grievous bodily harm to an officer.

He has also been refused bail and will appear at Parramatta Bail Court on Saturday.