Wellington, Dec 3 (DPA) The hole in the Antarctic ozone layer, blamed for global warming in the southern hemisphere, is shrinking and at its smallest for five years, New Zealand's National Institute of Water and Atmospheric Research (NIWA) said Friday.

Atmospheric scientist Stephen Wood said it indicated that international initiatives, such as the 1987 Montreal Protocol, which phased out chlorofluorocarbons (CFCs) and other ozone-depleting substances, may be working.

Wood said land and satellite calculations showed the Antarctic ozone hole reached a maximum of about 22 million sq km and an ozone mass deficit of approximately 27 million tons this year.

Last year, it was 24 million sq km and 35 million tons. The largest ozone hole ever recorded was in 2000, when it reached 29 million sq km with a 43 million ton deficit.

Although reluctant to say the ozone hole was recovering permanently, Wood said, "However, we have now had a few years in succession with less severe holes. That is an indication we may be beginning to see a recovery."

Continued monitoring would enable scientists to assess whether it was the start of a sustained, long-term, recovery, he said.

The Antarctic ozone hole forms in August and September every year and remains until breaking up in November or December.