The United Nations refugee agency UNHCR has urged the world to “not forget” Ukraine as the embattle country prepares to mark two years since Russia invaded.

The UN High Commissioner for Refugees Filippo Grandi said in a media conference the UN was “trying to say Ukraine should not take all the space” but as the war rages on and other conflicts emerge, the suffering of Ukrainians should not fade into the background.

About 6.3 million people who fled Ukraine remain refugees, mostly in other European countries, while nearly four million people are displaced within Ukraine’s borders.

“I don’t think we are yet at that stage of forgetfulness, but we are certainly at the stage where it is not a headline, and the sense of urgency that was there, which included humanitarian action, unfortunately, is not there,” Mr Grandi said as he was launching the UN’s 2024 response plan and a $US4.2 billion appeal for Ukraine.

Russia’s invasion in February 2022 created the fastest and largest displacement crisis in Europe in decades. Nearly two years later, the outflow of Ukrainians has substantially decreased, but the needs are still enormous.

Only half of school-age refugee children are enrolled in schools in their host countries and access to healthcare for many Ukrainian refugees is still a struggle, according to the UNHCR.

Also, the UN estimates that only 40 per cent to 60 per cent of Ukrainian refugees are employed. Many have only been able to get low level jobs below their qualifications.

The appeal for funds also heard that many people living on the front lines have “exhausted their meagre resources” and many refugees also are vulnerable.

About three-quarters of the total, $3.1 billion, is meant to support some 8.5 million people inside Ukraine. The remaining $1.1 billion is sought for refugees and host communities outside Ukraine.

UNHCR said a recent wave of attacks “underscores the devastating civilian cost of the war” and a bitter winter is increasing the need for humanitarian aid.

“In front-line towns and villages, people have exhausted their meagre resources and rely on aid to survive,” it said.

Ukraine has been subjected to massive Russian barrages recently. More than 500 drones and missiles were fired between December 29 and January 2, according to officials in Kyiv.

Nearly two years after Russia launched its full-scale invasion of Ukraine, the U.N. says 14.6 million people in the country need humanitarian help, while around 6.3 million have fled Ukraine and remain refugees.

“Hundreds of thousands of children live in communities on the front lines of the war, terrified, traumatized and deprived of their basic needs. That fact alone should compel us to do everything we can to bring more humanitarian assistance to Ukraine,” the UN’s humanitarian chief Marin Griffiths said.

“Homes, schools and hospitals are repeatedly hit, as are water, gas and power systems. The very fabric of society is under attack with devastating consequences,” he said.

Mr Griffiths said donors covered 67 per cent of last year’s appeal for $3.9 billion for people inside Ukraine, one of the best levels in the world. He said “the competition for funding is getting greater” because of crises elsewhere, including the war in Gaza.

“Amid everything else happening across the globe, we must stay the course for the people of Ukraine. And it is a very sad reminder that today we’re begging for attention for Ukraine when for so many days and weeks and months of previous years, we’ve had … attention to Ukraine and we’ve begged for attention for places elsewhere,” he said.