Green Party MP and minister Julie Anne Genter has given birth to a baby boy.

Photo: Julie Anne Genter

Ms Genter said in a post on Instagram she and parter Peter Nunns were overjoyed at the the safe arrival of their son at 6.03pm yesterday, weighing almost 4.3kg.

"We waited a very long time for labour to start, but when it did it was short and sharp," she said

"We are so grateful for the lovely staff at Auckland Hospital who provided wonderful care, for the incredibly experienced independent midwife who supported us the whole way, and for our amazing friends and family."

Photo: Instagram/ Julie Anne Genter

Ms Genter, Minister for Women and Associate Minister for Health and Transport, cycled on Sunday to Auckland Hospital where she was to have her baby induced.

The cycle ride made headlines from Brazil to Iceland while the ABC called it part of a well established theme where Ms Genter uses every opportunity to promote cycling.

Green Party co-leader James Shaw said at the time it was very 'on-brand' for Ms Genter to have chosen to ride her bike, and he was proud to be living in a country where two members of the country's executive were able to have children as part of their job

Prime Minister Jacinda Ardern returned from six weeks parental leave a fortnight ago following the birth of her daughter Neve Te Aroha.