"Burning children alive can never be justified. The whole world is mobilising to stop the Israeli genocide", the singer wrote on an Instagram story late Tuesday with the hashtag "#AllEyesOnRafah", which has been trending on social media.
Israel's military operations in Gaza, concentrated now on Rafah, provoked a renewed backlash after Gaza officials said an Israeli strike this weekend set ablaze a crowded refugee camp, killing 45.
American actor Pedro Pascal and model Bella Hadid also posted graphics with "All eyes on Rafah" on Instagram. Hadid has been vocal about her support for Palestinian rights, and has also called Israel's offensive as a "genocide".
In 2021, before the escalation of the Israel-Hamas conflict last October, Dua Lipa, Bella Hadid and her sister Gigi Hadid were described as anti-Semitic in an advertisement published in The New York Times by a Jewish group called the World Values Network.
Dua Lipa had hit back at the advert, rejecting the "false and appalling allegations".
While the pop sensation of Kosovan heritage has criticised the war in Gaza and been a vocal supporter of Palestinian rights, this is her strongest criticism yet of Israel's actions.
In January, Lipa called for a "humanitarian ceasefire" during an interview with Rolling Stone magazine. She had previously signed an open letter to US President Joe Biden calling for "an end to the bombing of Gaza and the safe release of hostages".
Forty people were arrested on Tuesday night in London following a pro-Palestinian demonstration of up to 10,000 people, UK police said.
Rock star Paul Weller, the rapper Stormzy and actor Tilda Swinton are among British celebrities who have previously called for a ceasefire in Gaza.