Vic security increased amid terror fears

Victorian authorities have stepped up security and counter-terrorism measures in the wake of the deadly Brussels terror attacks.

Victorians are being told that while vigilance is essential, there is no intelligence to suggest any heightened local threat as a result of the deadly attacks in Belgium.

"Victoria Police is doing everything it can to have the best intelligence, to be clear on what's going on and to be appropriate in terms of what's going on, but again I stress there is a need to be vigilant," Premier Daniel Andrews told reporters on Wednesday.

"(However) there is no intelligence to suggest any links between what's occurred in Europe, those tragedies and anybody in our state."

Victoria's chief commissioner Graham Ashton said police had ramped up counter-terrorism activities, including investigations and intelligence work overnight.

Airport security has been tightened and there is an increased police presence around transport hubs.

Meanwhile, a group of about 20 Belgians gathered in Melbourne's centre on Wednesday evening to hold a vigil for those killed or injured in the overnight attacks in Brussels.

They lit candles and placed handmade signs in French and Dutch on the steps of Federation Square, including one that read "make waffles, not war".

"It sends a strong message to Belgians that even with immeasurable human brutality, there is also love," Isis Zellit, 22, told AAP.

"And we are sending love from all over the world."

The law graduate organised the vigil because she thought it was important for Belgians living in Melbourne not to feel alone or isolated when they are thousands of kilometres from home.

Justine Massoulie, 26, is relieved her friends and family back in Brussels are safe, but saddened that fears about a terrorist attack in Belgium have become a reality.

"I've been worried that something like this might happen for about a year," the psychology graduate said.