Contract ended - job advertised

Hi
A friend of mine has been working for a company for a couple of years. Her contract expired at the end of Decemeber last and her employer decided not to renew it. Her job has now been advertised. She was given no indication that she was doing anything wrong, and not given a good reason for not renewing the contract. Can her employer do this? Can she reapply for the job?

Thanks as always for impending responses.

She can re apply and they dont have to renew her contract

There is some specific protection for temporary workers see [broken link removed]

Sorry no time for detailed reply, maybe post details about her written contract(s) (if any) and whether there was a temporary clause and if there was a clause excluding unfair dismissals