Chair Bob Cameron says the Mollison Street vaccination centre has been "inundated" with bookings that have stretched IT systems since the announcement Pfizer jabs would become available for 16 to 39-year-olds.

"Since the middle of the day yesterday - when that announcement was made - to now we have had over 5000 people register," he said.

Bendigo Health has also sent out invitations to another 4000 people who were already registered and waiting to become eligible for a vaccination.

More news: Victoria records 45 new locally acquired COVID-19 cases

More than 700 appointments this week have been snapped up in less than 24 hours.

The whole of next week has gone and the following week is expected to be fully booked out "extremely quickly", Mr Cameron said.

"My message is very simple. If you want to register, do it immediately.

"If you want to get the vaccine in September the opportunity is rapidly evaporating."

Mr Cameron said the vaccination centre was not accepting walk-ins.

Anecdotal stories are also emerging of waiting lists at GP clinics filling fast.

People trying to book at one Bendigo clinic watched waiting times swell from zero to 13 days within half-an-hour this morning and many are taking to social media to show screen grabs showing that sites are experiencing high volumes of traffic.

Premier Daniel Andrews yesterday said he would not be surprised to hear reports of sites crashing or of delays.

"I don't know if you can build a website big enough for over 1.2 million people who want to get vaccinated," Mr Andrews said.

"We are never happy to see systems overwhelmed, but it speaks to the point... [that] people want to get vaccinated really, really fast."

Mr Cameron expected more vaccination appointments to come online as soon as more Pfizer and AstraZeneca supplies arrived but it was still unclear exactly when that would be.

Bendigo Health this morning vaccinated its first 17-year-old with the Pfizer vaccine.

Tom Perrin said he was doing it to protect himself and his family.

"It's a first step to getting back to everything I want to do like graduating," the year 12 student said.

More news: Victorian records country's highest NAPLAN results

Tom was happy to be able to get his jab well before exams started but said he just wanted to get it over with as fast as possible.

He had blunt advice for any friends who might be hesitant about getting the vaccine.

"This is to protect people. You kind of have to suck it up, really."

Our journalists work hard to provide local, up-to-date news to the community. This is how you can access our trusted content: