Same name

Yes legal action can be taken by abc Ltd against wxyz Pvt. Ltd.  But it is necessary that the said trademark though not registered by abc Ltd should have been put to use since inception.  If you are unable to prove user of that the said trademark or establish the prior right or prove that the said trademark has not been used, then there are definite chances that you (abc ltd) can loose the legal battle. 

whether the division (wxyz)  of the parent company (abc Ltd.)  is using trade mark of the parent company? If it is not using trade mark of the parent company, then it  can not sue against another applied pvt.ltd for trade mark  registration.