The initiative, a European Parliament written declaration, seeks to halt the death penalty of Asia Bibi, a mother of five who was sentenced for blasphemy and has been imprisoned since 2010.
Bibi, a Christian, was sentenced to death for blasphemy after being accused of insulting the Muslim prophet Mohammed after she shared a drinking vessel with her Islamic colleagues.
The aim is to collect the signatures of more than half of the European Parliament's MEPs to a written declaration on promoting religious freedom in Pakistan and condemning the unjustified detention of Asia Bibi.
If that happens, the declaration will have the same legal value as a petition and will be sent to the High Representative of the EU and the European Commission.
Tajani, a former Commissioner, called on the EU to take "all necessary political and diplomatic action" to secure the release of Bibi and to promote religious freedom in Pakistan.
The EPP group member said, "Europe cannot be silent in front of the unjustified detention of Asia Bibi, a symbol of the persecution of Christians in the world. We have the duty to avoid the execution of a woman for an unacceptable crime."
He added that on 4 November 2014 a crowd of more than 1500 people had burned alive a couple accused of blasphemy in Pakistan.
"And two months ago, during Easter, a group of Islamists demonstrated in front of the buildings of the Pakistani government asking for the application of Sharia law in Pakistan and execution by death penalty for Asia Bibi."
"Every man or woman who cares about religion, human rights and is not blinded by hatred, knows that Asia Bibi has to live and should be released", said Tajani, who is also the European Parliament's Vice President responsible for interreligious dialogue.
The Primate of Australia, Archbishop Philip Freier, has also called for clemency in the Bibi case.
In his letter to the High Commissioner for Pakistan to Australia, he has asked that Islamabad re-open Asia Bibi's case and acquit her."