Family and friends say they are optimistic music icon Ian 'Molly' Meldrum will recover from injuries he suffered in a serious fall at his Melbourne home last night.

A gardener called ambulance officers to Meldrum's home in Richmond just before 7:00pm (AEDT), after Meldrum apparently fell around three metres down stairs while putting up Christmas decorations around his spa area.

He was in a coma and was taken to the Alfred Hospital in a serious condition. Shortly after his arrival, hospital staff upgraded his condition to critical.

This morning Meldrum's manager Mark Klemens told the ABC that Meldrum underwent "minor surgery" late last night.

"He suffered significant injuries to his chest area, shoulder-blade area, head injuries, [a] fractured skull and some injuries there," he said.

"The surgery was pretty straightforward. It was just to relieve some pressure [on his brain] as I understand it. That all went well."

Meldrum was in a critical but stable condition this morning.

"Really the next 24 hours are critical," Mr Klemens continued.

"He's in an induced coma and obviously that's the period of time that's going to be critical. We'll know more in 24 hours."

He described Meldrum as "fit as a fiddle" and said he was optimistic he would recover.

"Whenever he's been down before he's got straight up," he said.

"When he finally looks back on this he'll be humbled and so thrilled by the support."

This morning the neurosurgeon who operated on Meldrum overnight stressed that the star remained in a critical condition but said he was encouraged that the swelling on his brain had stabilised.

Professor Jeffrey Rosenfeld said Meldrum was not in an induced coma, saying instead that the star had been in a "deep coma" when ambulance officers got to him.

He said a brain scan would be carried later this morning to determine if any more surgery would be required.

"The next 24 hours is critical," he told reporters outside the hospital.

"I'm giving you a very early report but we are encouraged with the way he's going so far.

"I'm hoping that he will remain stable, not requiring any more surgery, and hopefully improve."

Family and friends have gathered at the hospital and long-time friend Gary Spry says he is hopeful the 65-year-old will recover.

"Everyone's pretty up [that] he'll be okay," he said.

"I mean, [for] anyone 65 it is a significant fall. I'm not a doctor. I can't give you the medical thing of it. I just heard everyone is pretty up that he will recover."

"He'll be fighting for his life," friend and music promoter Michael Chugg said. "He's not ready to bow out yet."

Mr Klemens said Meldrum kept himself in good condition and said he had been touched by the outpouring of support last night and this morning.

"It's quite extraordinary. The outpouring of concern and interest from everybody has been quite amazing and so quick. He is iconic, he's such a part of the Melbourne fabric."

Messages of support

Meldrum, a music critic, journalist and record producer, has been a part of the Australian music scene since the mid-1960s, starting out as the presenter on popular music program Countdown.

Easily recognisable in his trademark cowboy hat, Meldrum is also well-known internationally on the pop music scene.

For years he presented a regular music segment on Hey Hey It's Saturday and more recently appeared as a judge on Popstars and as a contestant in Dancing With The Stars.

He has interviewed a host of musicians and celebrities, including every single member of The Rolling Stones, as well as Prince Charles.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 2 minutes 44 seconds 2 m 44 s Samantha Donovan reports on Meldrum's condition Download 1.3 MB

Many people, including musicians and celebrities, took to social networking sites like Twitter to send well wishes to the icon.

"Sending my prayers to Molly Meldrum in Australia!" tweeted UK star Boy George, while Darren Hayes, former singer with Savage Garden, said: "Growing up, Molly Meldrum delivered all my childhood musical hopes and dreams directly to my living room. Get Well Soon."

"#LoveYouMolly Sending LOTS of love to Molly Meldrum ... Get well soon x :)", Kylie Minogue tweeted, using one of the two hashtags that was trending worldwide.

"Thinking of Molly Meldrum tonight" added her sister, Dannii Minogue.

Actor Russell Crowe added his message of support, tweeting: "Sending Ian Meldrum love. Thinking of you mate."

Peurto Rican pop star Ricky Martin sent his best wishes: "Molly, get well soon my friend! Sending much from Puerto Rico!!! #LoveyouMolly an #AustralianIcon", he tweeted.

Last month Meldrum helped honour his good friend and pop star Kylie Minogue when she was inducted into the ARIA's Hall of Fame.

Meldrum himself received an ARIA for special achievement in 1993.

He is also a prominent supporter of the St Kilda AFL team.

It is believed Meldrum shares his Richmond home with his long-term partner, Rui.