... when additional construction services which were not included in the initial contract but which were within the objectives of the original tender documentation have, through unforeseeable circumstances, become necessary to complete the construction services described therein, and the entity need to award contracts for the additional construction services to the contractor carrying out the construction services concerned since the separation of the additional construction services from the initial contract would be difficult for technical or economic reasons and cause significant inconvenience to the entity. However, the total value of contracts awarded for the additional construction services may not exceed 50 per cent of the amount of the main contract.
