Mr Marios, owner of the successful cafe-delicatessen The Olive Grove and pizzeria Nick's, is believed to have suffered a heart attack at his Nerrina home early this morning.

Born in Ararat in 1950, Mr Marios left school at the age of 13 to work with his father and family friends in cafes and greengrocers.

At 15, he took up boxing and a few years later became a bouncer.

He spent more than 20 years in the security industry working for hotels, nightclubs and as a personal bodyguard, before opening The Olive Grove in Sturt St, Ballarat, in 1996.

He opened Nick's at the rear of The Olive Grove in 2008.

Outside his restaurant ventures, Mr Marios had a passion for motorbikes and shooting and he was a member of the Ballarat Pistol Club and Ballarat Rovers Motorcycle Club.

He also loved rock 'n roll music and had an impressive display of memorabilia from that era.

Piano rocker Jerry Lee Lewis and Elvis Presley's guitarist James Burton were among his list of mates and his connections saw him invited to Sun Records 50th anniversary, held in the Gibson Guitar Lounge in Memphis.

Ballarat Mayor Judy Verlin remembered Mr Marios as ''a true Ballarat icon''.

''Nick could be best described as a loveable larikan, generous giant and a great big softie at heart,'' she said.

''He was fiercely loyal to his family and friends. Nick's stories will be sadly missed.''

Liberal Party Senator Michael Ronaldson said Mr Marios was very passionate about the Liberal Party and the right to vote in our democracy.

''In every step of the word he was larger than life,'' he said.

''From the party's point of view it will be a great loss; from Ballarat's point of view it will be a loss as well.''

Senator Ronaldson said Mr Marios' professional success could be seen every day by the number and variety of people visiting his businesses.

''The way he and (his wife) Vicky set it up and ran a business is a great story in itself,'' he said.

''He was an incredibly generous person and did a lot behind the scenes that very few people would be aware of.''

Mr Marios is survived by his wife Vicky and children Peter, Deanna, Alethea and Alexandra.