Barnaby Joyce and Vikki Campion's new baby boy Sebastian has been seen for the first time.

The baby was pictured sleeping soundly at Armidale Airport in New South Wales in the arms of his mother.

The couple welcomed their baby boy three weeks ago, and have kept the baby under wraps since then.

Dressed in a white baby suit with a hat, the baby was cradle in Vikki's arm while the former Deputy Prime Minister Joyce sat across from him.

Named Sebastian, the baby was born on Monday at Armidale Hospital and weighed eight pounds and seven ounces - 3.8kilograms - at birth.

The news of Ms Campion's pregnancy in February led to Mr Joyce's downfall as Malcolm Turnbull's deputy.

'We are very happy and just taking it quietly,' Mr Joyce told media on Friday afternoon

Former Deputy Prime Minister Barnaby Joyce and his partner Vikki Campion have welcomed their baby boy

The news of Ms Campion's pregnancy in February led to Mr Joyce's downfall as Malcolm Turnbull's deputy and leader of the Nationals

Baby Sebastian is Mr Joyce's fifth child and first son, and follows the four daughters he shared with estranged wife Natalie Joyce.

Mr Joyce celebrated his own birthday just a day later, turning 51 on Tuesday.

'We are very happy and just taking it quietly,' Mr Joyce told Fairfax Media on Friday afternoon.

Mr Joyce has previously said he did not want his child with Ms Campion, 33, to grow up 'as some sort of public display'.

He is understood to have requested personal leave in anticipation of the baby's arrival.

During the couple's first public comments on their relationship in February, Ms Campion said their son's middle names would be given in honour of her brother.

Named Sebastian, the baby was born on Monday and weighed eight pounds and seven ounces - 3.8kilograms - at birth

Baby Sebastian is Mr Joyce's fifth child and first son, and follows the four daughters he shared with estranged wife Natalie Joyce

Mr Joyce lost his cabinet position and the Nationals leadership after it was revealed he and Ms Campion, his former media adviser, were expecting a child.

Prime Minister Malcolm Turnbull later introduced a ban on ministers having sexual relations with their staff.

In a March interview Mr Joyce cast doubt on the paternity of the child, calling it a 'bit of a grey area', but later conceded those comments were a mistake.

When asked after the baby's birth whether the date ended any paternity doubts, Mr Joyce said that it did.