GLOBAL - The euro-zone sovereign debt crisis has seen the sustainability of pension systems across Europe decline, with a number of positive reforms undone by rising debt levels, according to Allianz Global Investors (AGI).

The company's Pension Sustainability Index also marked down a number of Eastern European countries - with Estonia, Hungary, Latvia and three other countries all using funds from the private pillar to boost their pay-as-you-go system.

Of all countries in the 44-strong index, Greece was singled out as in most in need of reform, followed by India, China and Thailand, as well as Japan - facing an increasingly ageing population.

Brigitte Miksa, head of international pensions at AGI, said: "At the heart of Greece's deteriorating ranking are acute sovereign debt, a quite serious ageing problem and a pension system that remains generous despite recent reforms."

Greece fell from third last to last compared with 2009's survey, while Sweden and Denmark successfully defended their ranking as best and second best European country, trailing only behind Australia and coming higher than the Netherlands - rising one place to fifth, but ranking behind new entrant New Zealand.

Miksa praised Australia's "lean" public pension, offset by what she deemed as a developed funded pillar and said this was the reason for many European countries ranking so highly.

"In a strong position are Sweden, Denmark, New Zealand and the Netherlands," she said. "As with Australia, these three western European countries have comprehensive pension systems based on strong, funded pension provisions."

Countries that ranked highly often therefore saw a low old-age dependency ratio on state benefits, with the UK coming behind Sweden but ahead of Denmark - with the UK in itself only ranking 14th in the overall table.

Renate Finke, author of the report and senior economist at the German asset manager, said the impact of the financial downturn had tested the resolve of several of the countries examined.

"In Central and Eastern Europe, for instance, some countries decided to put their hand into the proverbial pension-fund cookie jar in response to the dramatic rise in debt to GDP ratios," she said, citing Estonia, Hungary, Latvia, Lithuania, Poland and Romania.

"While such measures have ameliorated fiscal problems in the short term, they have depleted pension resources and affected long-term sustainability - hence, countries in Central and Eastern Europe do not rank as well this year as they did in previous indices."

Miksa also highlighted concerns about the adequacy of retirement benefits, although they were not considered in the index.

She said that, with a shift from pay as you go to funded and from defined benefit to defined contribution, the "crucial question" of adequacy would become increasingly important.

Miksa said it was questionable whether the current workforce, caught in these reforms, would be able to generate sufficient retirement income to avoid shortfalls or old-age poverty.