If you have had no income/gains that should have been within the Irish tax system for the last 5 years while you were non resident then there is nothing to be worried about coming back into the Irish tax system. For example if your only income was employment income over those 5 years and no duties were carried out in Ireland then there should be no issue. However if you had other income that should have been reported in Ireland for those 5 years i.e. rental income from the Irish property, then you will need to get your tax affairs up to date.
Also, depending on your sources of income there may be some tax planning opprtunities when you return. For example you will be taxed on the remittance basis of taxation for 3 years after you return. This means that Irish sourced income will be taxed in full but foreign income only to the extnet that it is remitted to Ireland.
Therefore, depending on the complexities of your case (taking into account sources of income etc) it may be worth getting professional advice.