The UK is likely to see "significant" numbers of Sudanese refugees arriving on small boats as war wages in their homeland - but a Ukraine-style legal route is not being considered, a minister said.
Tory immigration chief Robert Jenrick said he expected "new challenges" as a result of the devastating conflict.
But he said there were no immediate plans to make it easier for those fleeing the violence to reach the UK, amid calls for safe and legal routes to be expanded.
It comes after Africa minister Andrew Mitchell said a "humanitarian catastrophe" is unfolding in the region.
The Government is bracing for a brutal Commons battle tomorrow over its draconian Illegal Migration Bill.
Senior Conservatives - including ex-leaders Theresa May and Iain Duncan Smith - have called for a U-turn over plans to deny asylum seekers protection under trafficking laws.
And another group of Tory rebels has called for legal routes to be expanded - saying this will help stop people reaching the country via dangerous routes.
Asked about the impact of the Sudan war, Mr Jenrick said that "very significant numbers" of people are likely to flee Sudan in the coming days.
He said: "It is likely that in time there will be migratory effects of the crisis such as this. Sudan I believe has consistently been in the top 10 countries of individuals crossing the Channel on small boats.
"We should expect in time for this to lead to new challenges whether here in the UK or elsewhere in Europe."
Between 2018 and 2022 5,467 people from Sudan are known to have reached the UK by small boat, according to Government figures.
Mr Jenrick said: "Consistently we've argued as a Government that those in peril should seek sanctuary in the first safe country and I know the UNHCR (UN High Commissioner for Refugees) will be operating in those countries.
"We will do all we can through our development budget and other levers to support the UNHCR and those organisations that will respond when people arrive in those neighbouring countries."
The Prime Minister's official spokesman said: "At the moment our focus is on evacuating British nationals. The Home Office is keeping the situation under review."
Africa minister Mr Mitchell said there is going to be a "humanitarian catastrophe" in Sudan.
He told the Foreign Affairs Committee: "There is going to be a humanitarian catastrophe there with the position at the moment in terms of food and the humanitarian relief. Most of the humanitarian workers are leaving and they will not be able to come back until there is a ceasefire."
The minister added: "Five of them have already been murdered."
Asked if the Government should have seen this coming, Mr Mitchell said: "I think that is very difficult. My answer is no.
"This isn't an ideological battle, this is a battle between two generals for power. There is no ideology involved in this, it's raw power being fought over.
"One might have hoped that this would never happen given the appalling humanitarian jeopardy it has placed so many people in."
He added: "We would not have expected that these two generals would have slugged it out in this way on a totally non-ideological issue, let alone deploy heavy weapons in built-up areas."
A group of Tory MPs, led by Tim Loughton - who last year challenged Suella Braverman over legal routes - wants to see the bill include a concrete commitment to allowing people facing persecution to apply from abroad.
The Government has failed to do so, and Mr Jenrick said that only once illegal immigration is tackled can this be done.
Arguing for the bill's draconian measures - which would see children detained and deported and trafficking protection withdrawn, Mr Jenrick said: “More people are on the move – and those individuals are more mobile - than ever before… Geography is simply no longer the constraint it once was.”
“The consequence of this has been unprecedented amounts of illegal migration which has placed our public services under strain, weakened community cohesion and set back integration efforts.”
Following his speech, Enver Solomon, chief executive of the Refugee Council, said: "As we see right now in Sudan - one of the countries where people have no safe route to the UK - the world is as fragile as ever.
“The answer though is not as Mr Jenrick suggests to turn our backs on those who have to take dangerous journeys to reach our shores and to only allow those the government deems deserving to come.
"It is to thoughtfully and rationally work with the international community to share responsibility for providing safety and sanctuary to refugees and to address the reasons why people have to escape the terror they face.
“There are ways to navigate this challenge without resorting to divisive, unfair and inhumane legislation which indiscriminately locks up vulnerable men, women and children and then kicks them out of our country."
The bill will be put before MPs tomorrow.
Former Tory leaders Theresa May and Sir Iain Duncan Smith have put forward an amendment seeking to protect victims of modern slavery in the UK from removal and being barred from returning.
Mr Jenrick said he had "great respect" for the pair and said he would try to reassure them.
