Paris attacks: Max Key's touching message for Stephie

The picture on Max Key's Instagram account appears to be of him and his sister in Paris as young children. Photo / Instagram / Max Key

Max Key has posted a touching message for his sister Stephie following the Paris terror attacks.

The Prime Minister's son has posted a picture of what appears to be himself and Stephie as young children playing in front of the Eiffel Tower.

Max, whose sister is an art student in Paris, wrote: "My thoughts and prayers are with my sister and all those living in Paris. It's such a scary feeling being so helpless on the other side of the world, when someone you love is in that kind of situation! Stay safe."

Prime Minister John Key revealed on Saturday his moment of panic when news of the Paris attacks broke.

"She is at home now safe and sound but obviously like any parent, or anyone who has a loved one in Paris, it is a worrying time," he said on Saturday.

"Obviously we are hugely relieved she is safe and sound but obviously you are always concerned for your children and your family members and this is a time when there is a great deal of uncertainty in Paris. There may potentially still be some of these terrorists at large, so that presents risk."

Mr Key, who had just landed in Darwin on the way to Vietnam, said the he felt "numb" after hearing the news and expected others would too.

"It's a tragic day for the people of France and for any of the families of the victims involved."

"Our hearts go out to those involved and our thoughts are with them and their families," he added.

"It's the time that you always feel that distance between your own family members and somewhat helpless that there is not a hell of a lot you can do."