All British residents should qualify for evacuation from Sudan, Labour has said.
Downing Street has so far rejected calls to widen the eligibility for evacuation beyond British passport holders and their immediate family.
It comes amid criticism of the pace of the UK evacuation, which was bought more time after a three-day extension to the ceasefire was agreed.
Concerns have been raised that the current approach could see families split up or some members left behind, with Labour calling on ministers to use the longer window to extend eligibility for evacuation before it is “too late”.
Shadow Foreign Secretary David Lammy said: “It cannot be right that NHS doctors and other British residents who worked to protect us throughout the pandemic are being denied the chance to evacuate from the conflict gripping Sudan.
As of Thursday evening, the RAF had airlifted nearly 900 people from an airfield near the capital Khartoum.
“We do not underestimate the scale of the challenge faced by Britain’s brave armed forces and FCDO (Foreign, Commonwealth and Development Office) officials who are working around the clock, but the three-day extension to the ceasefire offers an opportunity to get more people to safety while the airlift is ongoing and there is capacity,” Mr Lammy said.
“All British nationals, close, dependent relatives of British nationals who are stuck and British residents seeking to flee Sudan should qualify to board evacuation flights. The government must act before the ceasefire ends and it is too late.”
The extension came after the paramilitary Rapid Support Forces joined the Sudanese military in agreeing to extend the 72-hour truce, which has allowed citizens and foreign nationals to flee.
Foreign Secretary James Cleverly has urged all UK nationals wishing to flee Sudan to come forward “as quickly as possible”, despite the extended truce.
Foreign Affairs Committee chairwoman and Conservative MP Alicia Kearns is also among those calling for wider eligibility, asking the Government to allow elderly people dependent on children who are British citizens to be admitted.