In a letter to the Speakers of Italy's lower and upper houses of Parliament Roberto Fico and Elizabetta Casellati respectively, Mattarella said lawmakers and the government must to "identify the ways and means" of amending the legislation.
The "severe" sanctions faced by charity boats that try to bring rescued migrants to Italy "do not appear reasonable in that no distinction is made between the types of vessels, the actual behaviour of their captain and crew or the identities of the people taken on board", Mattarella wrote.
Such massive fines and the impoundment of migrant rescue vessels are comparable to a criminal penalty, according to a recent ruling by the Constitutional Court, he said.
Mattarella recalled that under international law," any state must require the captain of a ship that flies its flag to go to the aid of whoever is in danger at sea, if doing so does not endanger the ship and those on board".
The letter also queried the "reasonableness" and "conformity with Italy's legal system" of a provision of the security law that makes arguing with a public official a criminal offence punishable with at least six months in jail.
The United Nations and the Council of Europe have voiced reservations about the security law, which critics have said it could undermine the human rights of asylum seekers and the victims of torture.
The UN refugee agency has said it is concerned that the measures against NGO ships will deter or impede sea rescues of migrants at a time when the European Union's Sophia naval mission in the Mediterranean is on hold.
( With inputs from IANS )