He was speaking at the opening of a Progressio photo exhibition in the House of Commons, where he was presented with messages from the British public calling for justice for crimes committed in poverty-stricken East Timor.
Mr Lewis said it was "incredibly important" to recognise the positive contribution that faith plays in solving some of the world’s worst problems.
He paid tribute to Catholic aid agency Progressio’s campaign, 'East Timor: Who Cares?', and the powerful testimony of Zequito de Oliveira, an East Timorese, who spoke at the launch of losing members of his family in the violence, including his two younger brothers.
“We politicians must always remember with our heads and our hearts,” said Mr Lewis, adding that the British government would continue to work through the United Nations and the EU to support East Timor.
The messages presented to Mr Lewis urge the UK to provide financial and technical support for a justice centre in the young South East Asian country to promote accountability for crimes committed during 25 years of Indonesian occupation from 1975-1999. During that time more than 100,000 people were killed.
Progressio’s Executive Director, Christine Allen said: “This year is the 10th anniversary of the East Timorese vote for independence - a show of bravery which must not be forgotten.
"A decade later its people are still waiting for justice. We believe the UK can play an important role in moving this process forward.
"Many hundreds of people have come out in support of our campaign – and our message is clear: we must not let the East Timorese people down. Justice must be done.”
Despite the work of local and international organisations to highlight crimes committed during the Indonesian occupation, justice remains largely undelivered and impunity is common place in East Timor. Campaigners say long-term peace and development in the new country, one of Asia’s poorest nations, will be impossible without accountability.
The House of Commons exhibition was hosted by Paul Goggins, Minister of State for Northern Ireland.
