Leukaemia is the most common cancer in children worldwide, accounting for a third of cancer cases in children nine and under.

More children than ever are surviving leukaemia in Australia and New Zealand but the outlook is much bleaker for children in poorer countries.

A study of 90,000 children diagnosed during 2005-2009 in 53 countries published in The Lancet Haematology has found the five-year survival in some countries is nearly twice as high for children in some countries compared to others.

The chances of a child still being alive five years after being diagnosed with acute lymphoblastic leukaemia (ALL) in Germany was 92 per cent, compared to 52 per cent in Colombia.

In Australia, between 1995-1999 and 2005-2009, five-year survival for childhood ALL - the most common childhood cancer - increased from 82.8 per cent to 88.8 per cent, according to the research.

Survival increased from 82.8 per cent to 89.3 per cent in New Zealand.

For Acute myeloid leukaemia (AML), the five-year survival increased from 53.4 per cent to 68.5 per cent in Australia, and from 67.6 per cent to 74.9 per cent in New Zealand.

Survival has improved for most age groups but remains lowest for babies under one.

Overall, children aged one to nine at diagnosis had higher survival for both types of leukaemia than those aged 10-14.

Survival has improved for most age groups, for both ALL and AML, especially for children diagnosed with ALL aged 10-14. It is still lowest for children diagnosed in the first year of life.

"There is room for improvement in the management of childhood leukaemia in many countries," said lead author Dr Audrey Bonaventure, London School of Hygiene & Tropical Medicine, UK.

According to the latest data on global childhood cancer incidence, published in The Lancet Oncology, leukaemia is the most common cancer in children aged 0-14 worldwide, accounting for a third of cancer cases in children aged nine and under, and a quarter of cases in 10-14 year-olds.

The rare disease, which accounts for an estimated 0.3 per cent of all cancers in Australia, leads to an overproduction of immature white blood cells, called lymphoblasts or leukaemic blasts. These cells crowd the bone marrow, preventing it from making normal blood cells.

Despite the improvements in five-year survival across many countries this accomplishment should not distract from the "dire" reality, says Professor Philippe Autier, University of Strathclyde Institute of Global Public Health at the International Prevention Research Institute in France.

"About 80 per cent of leukaemia cases in children occur in low-income and middle-income countries where there is little access to the sophisticated and costly specialised medical resources required for the optimum management of these conditions," Prof Autier said.