The 22-year-old man had earlier allegedly hopped into a Parliament House staff member's car and asked "where do you want to die?" before saying "I'm a psychopath and I'm off my meds".

The Sydney man, who has been in custody since the night in question, appeared in the ACT Magistrates Court via audio-visual link on Wednesday morning.

His lawyer, Mohamed Bejjaoui, formally entered pleas of not guilty by reason of mental impairment to charges of possessing an offensive weapon with intent and making a reckless threat to kill.

The Canberra Times has chosen not to name the 22-year-old defendant given the ongoing uncertainty about his mental health.

Police documents previously tendered to the court allege he got into the Parliament House staffer's car about 6pm on June 21, just after the worker had finished a shift.

The 22-year-old is said to have indicated he was "going to make himself comfortable" before asking the staffer things like "what's your life worth?"

"I'm down from Sydney," the man allegedly said.

"I'm here to stab someone. If it isn't you, it will be someone else."

He is said to have added "look, there's cameras to watch us" after noticing a large media contingent at the front of Parliament House.

Police claim the staffer drove around the building, fearing he would be stabbed as the 22-year-old pointed a knife with a blade up to 15cm long at him.

The worker eventually spotted some Australian Federal Police protective service officers and flashed his high beams at them before pulling up alongside them and explaining the situation.

According to police, the officers spoke to the armed 22-year-old through the car window and he handed them the knife at their request.

"While talking with the defendant, he stated that he wanted to talk to Scott Morrison," the police documents state.

"He would not elaborate on what he wanted to speak to the Prime Minister about.

"[He] only stated that the matter was classified and above the AFP [officers'] pay grade."

The 22-year-old Riverwood resident was ultimately removed from the car and arrested.

He has since made two unsuccessful bail applications, and Mr Bejjaoui said he would make a fresh bid for conditional freedom next week.

Magistrate Glenn Theakston listed that application for next Friday.

He also set another court date in September to progress the case.

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