Annie Tupou was more surprised than anyone when she found out she was pregnant at six months as she already had eight children under the age of ten.

Tupou found out she was pregnant at six months and had just gotten used to the idea of having her ninth child when she went into labour and ended up having twins.

"I never got dizzy or anything else ... I sometimes got tired like really drained out sort of thing but belly wise I wasn't showing that much," Ms Tupou told 9News.

However, her husband Russell, had a hunch she was pregnant and a doctor's appointment confirmed the happy news.

Tupou from McCrae on the Mornington Peninsula shared her story on Facebook in a mother's group.

"I had recently posted last week about tying my tubes after baby number nine as I literally found out a week and a half ago I was pregnant, and I was finding out this Thursday what I was having at my ultrasound," she wrote.

"Well I never made it to my ultrasound did I."

She thought she was having Braxton Hicks contractions until Tapou reached down and felt her baby's head.

"I reached down and my baby girl's head was half out!!!," Ms Tupou said in her post.

"I got into midwife mode as my hubby was in Sydney for work, I got blankets and towels ... and Twin A slid out straight away coming into this world at 3.45 am."

"I felt like I was in a movie," she said.

Three ambulances arrived and tended to the small baby, with mum and bub rushed to hospital.

At the hospital, Tapou was in considerable pain as she believed there was remaining placenta inside her, but a nurse quickly confirmed it was the second bub on the way.

"All these midwives ran into the room and I was like what's going on? And she said 'that's not a placenta that's another BABY!," Ms Tupou wrote.

"I was so shocked I just had another baby!!," she posted.

"Twin B was born at 5.45 am so my twin girls were born two hours apart."

The Tapou family is now complete, as the super mum thanked the hospital and the staff for looking after her twins, Tilila and Leylani.

"It will be a long road to recovery but they're here and now I have 10 kids under 10, five boys and five girls - my family is complete," Ms Tupou said.

The twins are expected to remain in the hospital for several months.

Photo credit: 9News