HE is perhaps one of the biggest bundles of joy in the country.

Weighing in at whopping 6.3kg, Maoama Ala was born almost twice as big as the average Australian baby.

His parents couldn't wrap newborn nappies around him or squeeze him into the clothes they had packed when he was born on Tuesday.

The Melbourne boy was born via caesarean section at 39 weeks after doctors became concerned about his size.

"They did scans and said he was a big baby, so they booked me in for a caesarean, but at the time they thought he was about 4kg," his mother Teuaililo Ala said.

"When he came out I was very surprised."

Moama weighed 6320 grams and was 60cm long. The average Australian baby tips the scales at 3.3kg.

Named after his father, the healthy boy has set a record at Sunshine Hospital as the largest baby ever born, beating the previous record by 90g.

He is the fourth child for the couple, who are originally from Samoa, but lived in New Zealand for many years before moving to Australia.

His siblings, nine year old twins and a six year old, only weighed between 3-4.5kgs.

"The other children are really looking forward to having a baby in the house again," Mrs Ala said.

"They are so excited they are talking about taking turns staying home from school to look after him."

As for Maoama, he's largely oblivious to his grand entrance to the world, blissfully sleeping and feeding his way first few days of life.