Help needed please..........

We brought two house rabbits two weeks ago for my step daughter who stays with us at weekends, we really want the rabbits to use our house as their home, but they don't seem to want to come out of their cage........

I have been putting food just outside to encourage them out, but once they have ate it, they go back in............

I did think about taking them out and shutting the cage so they cannot get back in until bed time, to encourage them to explore the house, but is this cruel keeping them away from where they feel safe?

They are both very nervous and any advice on how to encourage them to get involved with us would be appreciated.