"Let's be clear - what is happening in Gaza is the slaughter of Palestinian people by an aggressive Israeli regime with high schools and creches among the buildings targeted," Chuilin said.
"All the civilian deaths in Gaza, including those seeking shelter in a UN school are indefensible and unjustifiable," she said, the Islamic republic news agency reported.
In an article published in the latest edition of North Belfast News, Chuilin warned that "tough words alone will not move the Israeli government."
"It is clear that the Israeli government is not listening. The timing of the current Israeli offensive was as calculated as very other aspect of these operations," she said, adding that it is directly linked to Barack Obama's move into the White House.
"The Israeli assertion that its operations are in response to Hamas' rocket attacks is threadbare. The rocket attacks should cease," she said.
"But the days of Israel using the excuse of security to slaughter innocent Palestinians must be brought to an end," she warned.
Chuilin was elected as a member of Belfast's devolved assembly in 2007. Previously, she served four years in prison on explosive charges during the armed struggle against British rule.
She expressed support for a demonstration against Israel's invasion organized in Belfast on Saturday by the Irish Palestine Solidarity Campaign.
"Come along to add your voice to the thousands all over Europe and the Middle East who are calling for an end to the slaughter in Gaza," she said.
Separately, Sinn Fein two members of the European Parliament, Bairbre de Brun and Mary Lou McDonald are calling for a suspension of the EU-Mediterranean Association Agreement, which underpins preferential trade with Israel.
Chuilin said that she was calling for the Irish government to press for a suspension at EU level and that all international leaders should consider this approach and others to bring about an end to the killings in Gaza.
"World peace and stability is in the interests and responsibilities of all sovereign nations and that includes peace in the Middle East," she said.