A MAN has been hospitalised after illegally climbing the Harbour Bridge this morning in an almost six hour stand-off with police.

The climber plunged the city into a standstill after he scaled the structure just before 4.30am this morning.

Police finally arrested the man, who is from Woolloomooloo, just after 9.30am, following hours of negotiations.

We can confirm the man is in police custody and is safe. More to come — NSW Police (@nswpolice) April 3, 2018

A man remains in hospital after a stand-off with police on the Sydney Harbour Bridge lasting almost six hours https://t.co/w1bh2m9Wzx — NSW Police (@nswpolice) April 4, 2018

Detective Inspector John Maricic told reporters the man is now in St Vincent’s Hospital undergoing a medical assessment.

He said the climber has “significant mental health issues” and that his motive was based on a “family issue”, on which he would not elaborate.

“Police hope to speak with the man, who is from Woolloomooloo, once he is considered well enough,” a statement read.

He confirmed the man is known to police, and was engaging with the rescue squad and unit of negotiators early on.

He apologised to the public for the three-hour traffic delays, saying police had concerns the man could have come into contact with a member of the public had he fallen.

He said the man will be “significantly charged” once he has received the appropriate medical care.

Moments before his arrest, the man had climbed out of his enclosure and yelled “Get out of the f**king car!” to police on the road, Fairfax Media reported.

He then moved towards two rescue officers and was arrested, handcuffed and led down to the bridge’s elevator.

The unauthorised climber had perched himself on the infrastructure in the middle of the bridge, with earlier reports he was shouting at police and refusing to come down.

The man could be seen on the footage wearing headphones and rolling a cigarette from within the enclosure.

The headphones were still in his ears when he was brought down by police.

The man was wearing a cap, a tracksuit top and fingerless gloves.

The footage showed the man scampering further up the bridge as police got close to him.

At one point, he made a hand gesture to police that appears to suggest they call his mobile phone.

NSW Police have not confirmed whether or not he is known to them, and his motives remain unknown.

According to Sunrise, the man was demanding to speak with senior government officials, but police would neither confirm nor deny these reports.

It’s believed he left a bicycle in the middle of the road before making the climb.

Sydney Harbour Bridge: A man has illegally climbed the southern arch of the bridge. Some lanes closed in both directions due to the police operation. Lengthy traffic jams both sides of the bridge. Live updates on @sunriseon7. https://t.co/jKxA4LcbjG #SydneyHarbourBridge #7News pic.twitter.com/evMrLI0p36 — 7 News Sydney (@7NewsSydney) April 3, 2018

SYDNEY TRAFFIC THROWN INTO CHAOS

The operation has thrown peak-hour morning traffic into chaos across the city this morning, with south-bound traffic delays stretching 20 kilometres at one point.

All lanes have now been reopened on the Harbour Bridge, but there are still significant delays.

A Transport Management Centre spokeswoman told news.com.au the congestion is beginning to ease following the man’s arrest.

“Now that peak hour is over, hopefully the delays won’t last much longer,” she said. “We’re still telling people to stay aware and factor in extra time.”

She said the southbound side is now backing up to Artarmon, nine kilomentres from Sydney’s CBD.

The northbound side is now stretching back to Huntley’s Point.

She estimated the delays would continue until around 10.30am.

North Shore Line, Northern Line and Western Line trains remain unaffected, but buses across the bridge faced earlier delays of up to 70 minutes.

Angry commuters have been venting their frustration all morning over the delays.

Stuck in traffic cause of an accident on the harbour bridge and I'm on my way to an appointment and I'm so stressed agskdndjsjskd — em (@emmaaclaire) April 3, 2018

Gr8 now I’m late to work because someone decides to climb the harbour bridge early this morning w no harness 🙄 — Adi Alisi 🇫🇯 (@aliceebreezie) April 3, 2018

At the second last stop they decided to tell us that the Harbour Bridge is closed so this bus will be going somewhere totally different and we need to get trains into the city 🙃 — Josh of Zur-En-Arrh (@Mario__Bones) April 3, 2018

In 2011, Sydney father Michael “Mick” Fox sparked a similar standstill when he climbed the Harbour Bridge as an act of protest.

The former elite soldier used a ladder and ropes to scale the structure because he wanted to gain access to his children.

Climbing the Harbour Bridge is illegal unless authorised.