Sydney Aust's top terror target: Scipione

Iconic tourist spots such as the Opera House, Harbour Bridge and Circular Quay make Sydney the nation's foremost terror target, says NSW Police commissioner Andrew Scipione.

A security upgrade will be given to renowned venues, airports and public events, including NRL and AFL final matches, and other well-known public buildings, such as the NSW parliament.

It comes after Prime Minister Tony Abbott announced Australia's terror level would be elevated to high for the first time in the nation's history.

Mr Scipione said it is only natural that NSW, as Australia's largest state would be the top target for terror attacks.

"To say anything other than yes would be wrong," Mr Scipione said.

"Certainly in terms of world cities, this is arguably Australia's world city."

"That in itself means we are going to be likely greater targets."

NSW Premier Mike Baird assured there was no specific threat but said people must be vigilant and patient in the light of new security measures.

"There is no cause for panic. But there is cause to take further measures to protect the lifestyle we cherish," he said.

While there should be no changes to what can be taken to sporting matches or through airports, beefed-up security is expected to cause delays.

Mr Scipione said the public should expect to see extra security at public events as well as around public transport.

The premier dismissed concerns that far right groups could take advantage of the elevated terror level to cause divisions within the community, such as during the 2005 Cronulla riots.

"This is not about religion. This is about criminals intending to act criminally in association with terrorism organisations," Mr Baird said.

"Anyone thinking about acting like that, we will hunt them down."

Mr Baird's personal security detail will be also be reviewed by security agencies.