The migration crisis in Europe "plays directly" into issues around the UK's renegotiation of its EU membership, Foreign Secretary Philip Hammond says.
He said the crisis was "focusing attention" on the challenges large-scale migration across the EU presents.
EU migration is one of the issues the government wants to address in its renegotiation of Britain's membership.
His comments come ahead of an EU summit on the migrant crisis later, which David Cameron is due to attend.
The PM is expected to urge EU leaders to provide more support to vulnerable people in Syria and the wider region.
Europe is struggling to deal with a vast influx of migrants and refugees reaching the continent - most fleeing conflict in Syria but large numbers also fleeing violence and poverty in Afghanistan, Eritrea and Kosovo.
On Tuesday, EU interior ministers agreed a mandatory plan to relocate 120,000 migrants across the continent, despite opposition from some European countries.
The UK has opted-out of the quota system but has agreed to take in 20,000 refugees from the camps bordering war-torn Syria over the next five years.
Speaking in Brussels, Mr Hammond said: "This migration crisis has thrown into stark relief some of the issues the EU has to deal with - and that plays directly into some of the issues we are are raising in our renegotiation proposition."
He said some of the countries most hostile to challenging the principle of freedom of movement were now "focusing attention" on the problems of large-scale migration within Europe.
'Separate but related'
"The two things are separate but they are related," he told reporters, adding "and that's been our argument all along".
He said he did not know whether or not it would end up helping the UK's case as it seeks to reform Britain's membership of the EU ahead of an in/out referendum on UK membership.
Mr Hammond also played down talk of a quick renegotiation deal - ahead of a referendum that must happen by the end of 2017.
The government is ramping up diplomatic efforts to put the UK's EU reforms back on the agenda and persuade other EU countries to back it, following a summer dominated by the migration crisis.
In the latest stage of the government's campaign to convince other leaders of Britain's case, Mr Cameron met French President Francois Hollande at his country residence, Chequers, on Tuesday.
Mr Hammond is to hold meetings with officials in Brussels on Wednesday.