UNHCR is preparing for up to four million people that will arrive into neighbouring countries

The United Nations refugee agency, UNHCR says at least 150,000 refugees have fled Ukraine to neighbouring countries in the wake of Russia's assault on Ukraine.

Ukranian refugees offered warm clothes as they arrive at the Medyka border crossing, Poland Source: AAP

The latest figures come after the UN says it plans to seek over $1.3 billion in donations for humanitarian relief in Ukraine over the next three months.