The House, at the Centenary Hospital for Women and Children, has been at or near 100 per cent capacity for the past three months.

Executive officer Michelle McCormack said if the demand continued the charity would look to increase their size.

Ronald McDonald House supports families with seriously ill children, providing accommodation for those who don't live locally. About 1053 families have utilised the facility since it opened in October, 2012.

However, recently they had been in the "horrible position" of having to turn families away.

"If we continue at the high occupancy rate that we are, then the question needs to be asked if 11 rooms are enough," Ms McCormack said.

The house was recently awarded the inaugural charity award at the Telstra Business Awards, for its work supporting people in need like Eleanor Brown.

The Bermagui mum of four found herself in Canberra when her twins were born prematurely at 31 weeks.

Six weeks ago her husband Robert took her for a check-up at Moruya hospital, and Mrs Brown gave birth to baby girls less than five hours later.

After a quick hold, the girls flew "first class" to Canberra, where they were supposed to be born in the first place.

"Everything was normal, and then at 31 weeks I was just really emotional and didn't feel right," Mrs Brown said.

"Within hours, we were parents."

The day after the birth, Mr and Mrs Brown joined their babies in Canberra with nowhere to stay.

"We came knocking on the big red doors, and sure enough they had one room left for us," Mrs Brown said.

For the Browns, the Ronald McDonald House has proved essential. Without the facility, Mrs Brown said the family would not have had the funds to stay for six weeks while their babies were in hospital.

Ms McCormack said it was rewarding to see the house supporting families like the Browns.

"This is the first time since we opened that we've had a sustained period of high levels of occupancy."

She said the house would have to run at the same levels for 12 to 18 months before more rooms were added, to ensure it wasn't just an irregular peak.

Meanwhile, the Browns hope to take their daughters home soon.