SURPRISE: "I thought it was just me overeating," says Timaru woman Sharon Watts of her 35kg ovarian cyst.

A massive cyst has been removed from a Timaru woman in what could be a New Zealand record.

Sharon Watts had no idea she was carrying the 35 kilogram ovarian cyst around until last Thursday when she was admitted to Timaru Hospital with stomach pains.

The pains started two weeks ago.

"I had been to my doctor two weeks ago and I went home and had a sore stomach; I took some pain killers and then it was comfortable.

"The pain started again last Thursday so my husband rang my doctor.

"I went to see my doctor who examined my stomach and said it was full of liquid."

Mrs Watts was sent to Timaru Hospital for a scan.

Gynaecologist Albert Makary said he had never seen anything that size.

"It was almost the weight of 10 babies; I don't know anyone in my career who came across something that big, I think the world record is 50kg."

Mr Makary said cysts between 12 and 13kgs were more common and were often hard to spot. Often people did not know they were developing.

Mrs Watts was immediately admitted to hospital and the tumour was removed on Friday in a four-hour operation.

"It's been sort of like a dream really; it's been surreal," she said.

"I had put weight on but I didn't have any suspicions; I thought it was just me overeating.

"There's been no clues of me being sick; just me being overweight, it feels really good now."

She described it as an unlikely Christmas present to give away.

The cyst has been sent to the laboratory for testing and Mrs Watts is expected to be back home with her family for Christmas Day.

"I'm hoping everything is going to go well ; I haven't got back on the scales yet; I just don't like scales and I'm too scared.

"I can actually fit some of my clothes now which is nice; I was wearing a 5XL T-shirt and I couldn't understand why.

"It's a great end (to the year) and a great start to 2013; I will be able to go out healthier than I was."