Hi all, I wonder if anyone can give me some advice.....

My partner has just moved in with myself and my 2 young children ( aged 3 & 4) and he has brought his 18 month old cat with him. She is a very loving cat and quite sociable normally, even with new people, well adults at least. When we brought her to her new home for the first time the children weren't around and it didn't take her long at all to be seemingly quite comfortable and at home. When the children came back from their fathers after the weekend however she has been terrified. She has been hiding behind the microwave all day until the kids go to bed. Once they are in bed she comes out and is pretty much normal. I do know that this is the first contact she has had with children, and my 2 aren't the type that will chase her round and try to poke and prod her. Is there anything i can do to make this easier? I really don't want the cat to feel frightened in her new home.