TOKYO - The organisers of the 2020 Tokyo Olympics have vehemently denied an accusation by an environmental group that several of the new Games venues are being built by wood that has been purportedly obtained through illegal logging.

The US-based Rainforest Action Network (RAN) said on Monday (Nov 12) that the use of wood from Malaysia and Indonesia to build new Games venues "flies in the face" of Tokyo's commitment to realise the United Nations' sustainable development goals.

"Unfortunately, Tokyo 2020's substantial procurement of unsustainable tropical timber has already undermined this pledge," the group said in a scathing 12-page report titled Broken Promises. This is due to the "illegal logging, human rights abuses, and high deforestation rates that have been widely documented in both the Malaysian and Indonesian forestry sectors and given what is known of Tokyo 2020's plywood suppliers".

But Tokyo 2020 spokesman Masa Takaya told The Straits Times: "It is a matter of fact that all timber currently used in construction for the Tokyo 2020 Games has complied with its sustainable sourcing code for timber."

This code, which includes feedback from various stakeholders including experts in human rights and the environment, was drafted to ensure the sustainability of all procured timber in the construction work for the Tokyo 2020 Games.

Nonetheless, Mr Takaya added that Tokyo has, since July this year, been holding discussions on whether to further enhance the code.

The RAN report accuses Tokyo of going against its own pledge to use timber that is "harvested through logging activity that is considerate toward the conservation of the ecosystem".

The Games is already plagued by controversy over delays and mounting cost overruns.

Last month's relocation of the 83-year-old Tsukiji fish market to Toyosu to make way for a road to improve access from central Tokyo to the Tokyo Bay area, where some Games facilities are located, came two years later than schedule over pollution concerns at the new site.

Further, the Board of Audit estimated last month (Oct) that total spending for the event will reach at least US$25 billion (S34.5billion) - more than four times the original budget.

Japan is the world's largest global consumer of tropical plywood, mainly from Malaysia and Indonesia, and this is the second time RAN has questioned the Tokyo Olympics over its wood sourcing practices.

In April last year, the group was one of seven environmental organisations that urged Tokyo to stop using cheap timber at the new National Stadium, a wooden latticed centrepiece designed by renowned architect Kengo Kuma.

They said that some of the timber had come from Malaysian logging giant Shin Yang, which has been accused of deforestation and human rights violations. The Games' organisers had, at the time, confirmed the use of Shin Yang timber but stressed that the wood met certification standards according to its sustainable sourcing rules.

RAN said on Monday that the practice has continued despite the initial report, noting that at least 134,400 sheets of tropical plywood from Malaysia and Indonesia were used as the concrete framework for a series of new Olympic venues as of May this year.

For instance, wood from Shin Yang, which has denied the allegations, was found at the Olympic Village construction site in December last year, RAN said.

Meanwhile, it added that tropical plywood from Korindo - an Indonesian company accused of illegal logging and human rights abuses, as well as using fire to clear land that contributed significantly to the haze that affected Singapore in 2015 - has been used to build the new Ariake Arena, the planned volleyball venue in the Tokyo Bay area.

Citing photographic evidence and company supply chain data, RAN said there was a "high risk that wood supplied to the Tokyo 2020 Olympics was tainted and illegal".

Japanese timber and building materials trading company Sumitomo Forestry, however, has asserted to RAN that it has "only supplied legally sourced timber".

The group added: "Olympic organisers have defended their use of Korindo wood on grounds that its supplier, Sumitomo Forestry, assured them of compliance."

According to RAN, tropical deforestation has picked up pace over the last 10 years despite increasing global attention - and commitment - to climate change.

Last year, tropical forests covering an area of 158,000 sq km - or 40 per cent the size of Japan - were lost. This was marginally lower than the record area set in 2016.

"The timber procurement practices of the Tokyo 2020 Olympic organisers and Japanese companies have already compromised the sustainability credentials of the Tokyo 2020 Olympics," RAN said. "They further risk undermining Japan's commitment to the sustainable development goals, which aim to halt deforestation and restore degraded forests by 2020."