A Japanese government official said on Thursday he had not heard of a reported $600 billion IMF lending facility to help the euro zone, although Japan would consider providing bilateral loans to the Fund if warranted by developments in Europe.

The Nikkei newspaper reported earlier that the Group of 20 nations were planning to assemble the lending facility and that it could be used to bolster euro zone countries.

Key members like Japan, the United States and China would contribute to the facility, the Nikkei said.

The official called the report speculation among speculations.

I generally hear such discussion as each country may provide bilateral loans to the IMF, the official, who declined to be named, told reporters.

I'm not aware of any concrete talks taking place as to whether, when and how much of such contribution would be made as there's no substance to how the IMF would support Europe.

A South Korean G20 officials also denied there were any new developments concerning the International Monetary Fund's lending capacity.

There's no progress made on the matter of seeking ways to boost financial resources at the IMF since the Cannes (G20) summit, he told Reuters.

The comments follow denials from the IMF itself and G20 member Canada.

There are some nuances to the positions of some countries, but I assure you there has been no commitment by the G20 to any specific resourcing plan, Finance Minister Jim Flaherty told reporters in Ottawa.

The Japanese official said Tokyo regarded bonds issued by the euro zone's rescue fund as safe assets, even after Standard & Poor's warned that it was considering downgrading the EFSF depending on whether the six triple-A rated nations in the euro zone are cut.

We still consider (EFSF bonds) as safe assets and will continue to buy them at a certain rate in accordance with liquidity, the official said.

We will consider lending support to the IMF and EFSF purchases depending on the situation in Europe, the official said.

Japan has so far bought roughly 3 billion euros, about 20 percent, of the total bonds issued by the European Financial Stability Facility (EFSF) that is financed by member governments, making the country a major contributor.

The IMF denied the Nikkei report, and a G20 official also said it was untrue

Japan has lent $100 billion to the IMF in the wake of the 2008 global financial crisis.

(Additional reporting by Yoo Choonsik; Editing by Chris Gallagher and Tomasz Janowski)