Vic on alert following Sydney siege

Authorities are on high alert in Melbourne, as a hostage situation continues in central Sydney.

The Lindt store in Melbourne's CBD has been closed as a precaution with a gunman holed up in the same store in Sydney.

Uniformed police are also conducting high-visibility patrols across Melbourne.

Premier Daniel Andrews said police have not received any threats.

"There is no specific threat that is known or posed by these events to Victoria, or to Victorians," Mr Andrews told reporters on Monday.

"Having said that, it is important that we monitor what is going on in Sydney as it unfolds."

"We hope it ends peacefully, we hope it ends swiftly."

Mr Andrews said it appeared to be an isolated incident, and he called on the community to report any suspicious activity to police.

Victoria Police deputy commissioner Tim Cartwright said police were also reviewing security arrangements for major events over the next few days.

"We have also been in contact with our Islamic community friends," Mr Cartwright said.

"We will continue to be in contact with all leaders from different cultures."