I was just told to turn on my telly - possible terrorist-led siege is current in Martin Place, Sydney with hostages reportedly being forced to hold up ISIL flags.

Up to 13 hostages have been held by the terrorists in the Lindt Café in Martin Place.

Link to News Ltd website with some early information.

Large portion of the surrounding CBD area in lock down.

http://www.news.com.au/national/a-man-is-holding-several-people-hostage-at-martin-place-cafe/story-fncynjr2-1227156241649.

Airspace above Sydney shut down and incoming travellers diverted.

City Circle and Eastern Suburbs underground rail lines have been shut down. Scene is close to the head offices of the Reserve Bank and Australia's two largest savings banks, ATN-7 news studios and the NSW Houses of Parliament.

http://www.news.com.au/national/martin-place-cafe-siege-some-sydney-trains-cancelled-buses-diverted/story-fncynjr2-1227156313698.

Sydney Opera House has been evacuated.

Houses of Parliament have been evacuated.

Evacuations of surrounding buildings are continuing.

ATN7 news studios have been locked down.

http://www.news.com.au/national/breaking-news/seven-evacuates-newsroom-near-cafe-siege/story-e6frfku9-1227156337550.

NSW Police Force snipers have surrounded the scene.

The Prime Minister's Office has released a statement. Commonwealth resources have been offered to the NSW Government.

The Sydney Harbour Bridge has been shutdown. No trains (North Shore Line) or road traffic passing over at this time.

Public transport outside the CBD is still running though.

International coverage - this from the BBC.

http://www.bbc.com/news/world-australia-30473983.

Coverage from CNN.

http://edition.cnn.com/2014/12/14/world/asia/australia-operation/index.html?hpt=hp_t1.

Coverage from the New Zealand Herald.

http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=11374445.

Sydney Hospital (at the east end of Martin Place) has reported that a suspicious package has been left by an unidentified person inside the hospital. It is yet to be confirmed what the package contains and if it is related to the siege.

There is a report of arrests being carried out in the suburb of Lakemba that may involve people who assisted with the organisation of the siege.

A report of an arrest outside the scene of the siege has been received by Ch 7.

One arrest made and a handgun supposedly carried by the suspect has been made safe. This occurred about 200 metres from the siege scene.

The number of hostages taken has been revised to approximately 50.

The arrest mentioned above apparently is not related to the siege. Good work by the Police to get another handgun off the streets though.

Airspace closure reports are not correct. Planes to and from Kingsford Smith Airport are being diverted around airspace currently occupied by police helicopters.

Rail services on the City Circle and Eastern Suburbs lines are operating but trains are skipping Martin Place Station.

The Sydney Harbour Bridge and Cahill Expressway are both closed until further notice.

The standoff has entered its fifth hour. No change in the situation yet.

The Prime Minister addressed the Nation earlier and other world leaders are being brought up to date on the chain of events.

Ray Hadley at 2GB said he has spoken to one of the hostages to relay demands from the gunmen though has refused to speak to either hostages or the gunmen live to air on police advice.

The afternoon traffic peak is due to begin. It will be a long and slow trip home this afternoon, especially for those using the bus network.

I am very sorry to say that ultimately, this sort of event was inevitable.

Only takes on nut with gun.

Hope all of those whom are held against their will get out safely.