The coronavirus pandemic has severely affected children's rights worldwide, with young people risking a "generational catastrophe" if governments do not act, a rights group said in an annual survey Thursday.

Millions of children have missed out on education because of Covid-19 restrictions while there will be a long term impact in terms of their physical and mental health, Dutch NGO KidsRights said as it launched its annual ranking.

The survey ranks Iceland, Switzerland and Finland as best for children's rights and Chad, Afghanistan and Sierra Leone as the worst, out of a total of 182 countries.

Marc Dulleart, founder and chairman of KidsRights, said that the effects of the pandemic on children had "unfortunately exceeded our predictions at the outset last year".

"Apart from patients of the coronavirus, children have been hardest hit, not directly by the virus itself, but fundamentally failed through the deferred actions of governments around the world," he said.

"Educational recovery is the key to avoiding generational catastrophe," Dulleart added.

The group said schools for more than 168 million children have been closed for almost a full year, with one in three children worldwide unable to access remote learning while their schools were shut.

An additional 142 million kids fell into material poverty as the global economy was hit by the pandemic, while 370 million kids missed out on school meals.

KidsRights paid tribute to Manchester United and England footballer Marcus Rashford for his campaign to extend free school meals.

It also hailed Bangladesh for taking over a national TV channel for home schooling and praised Belgium and Sweden for trying to keep schools open.

Meanwhile 80 million children under the age of one could miss out on routine vaccination for other diseases because of disruption to healthcare systems, it said.

The report said there was also an "astonishing increase" in domestic violence during lockdowns, with children often the victims.

KidsRights included Palestine on its list for the first time, placing it in 104th position due to a focus on healthcare despite difficult circumstances.

However, as in previous years it gave low scores to Britain, Australia and New Zealand, due to a lack of legal protection for children relative to their wealth.

Britain and New Zealand were ranked at 169 and 168 respectively, below North Korea, Syria, Iraq, and Sudan, and just ahead of Eritrea.

Austria and Hungary also fell heavily due to discrimination.

The survey uses UN data to measure how countries measure up to the UN Convention on the Rights of the Child.