Greenpeace on Thursday said a promised moratorium on deforestation would have little impact on Indonesia's huge carbon footprint unless it is extended to existing concessions.

The environmental group also urged President Susilo Bambang Yudhoyono to begin the moratorium immediately instead of next year to prevent major new concessions being granted in the interim.

"The destruction of forests is still massive. President Yudhoyono needs to act fast," said Greenpeace Southeast Asia forest campaigner Zulfahmi.

Yudhoyno announced the two-year moratorium in Oslo last month, cheering environmental activists but sending shudders through the country's massive palm oil industry blamed for much of the country's forest losses.

In exchange for verifiable cuts in deforestation, the Norwegian government agreed to provide a billion dollars in aid to help Indonesia preserve its forests.

Environmental groups have welcomed the initiative but say the details remain vague and question whether it will do much good as long as logging continues on existing concessions covering 1.8 million hectares (4.4 million acres).

"Without intervention on existing concessions, the president cannot achieve his commitment to reduce Indonesia's greenhouse gas emissions even by the promised 26 percent with or without international help," he said.

Yudhoyono has promised to cut Indonesia's emissions of climate-heating gases by 26 percent by 2020 and by 41 percent with international assistance.

Experts say Indonesia's forests are disappearing at a rate of about 300 football fields an hour, releasing vast amounts of greenhouse gases blamed for global warming.

A report by a coalition including the BlueGreen Alliance and the Rainforest Action Network released in the United States last month found that 40 to 55 percent of Indonesia's timber is illegally harvested.

It warned that 98 percent of the archipelago's lowland forests could be gone by 2022.