TOKYO, Aug 1 (AFP) - Japan took a step closer Monday to indicate its support for a proposed US national missile defence shield which has agitated Russia and China.

Prime Minister Yoshiro Mori said in parliament that his country understood the United States was examining the so-called National Missile Defencescheme from the standpoint of its own security.

Japan had been noncommittal on the NMD while it was engaged in joint research with Washington to develop a Theater Missile Defense (TMD) shield covering allied nations and US bases there.

"Our country for its part understands that the US administration is studying the NMD plan by taking the proliferation of ballistic missiles in recent years as a serious threat to the security of its nation," Mori said.

"We hope that consultation between the United States and Russia on this issue will be coordinated," the premier told a full session of the upper house.

"I also wish that the issue will be handled in a manner conducive to an improvement in the international security environment."

Japanese leaders had previously stated the NMD issue should be solved between the US and Russia.

Russian President Vladimir Putin issued a declaration with his Chinese counterpart Jiang Zemin, urging the US to abandon NMD, when he visited Beijing last month ahead of a Group of Eight summit in Japan.

Putin also secured North Korea's pledge to halt its missile development program in exchange for access to space rocket technology when he stopped in Pyongyang for talks with North Korean leader Kim Jong-Il on his way to the July 21-23 G8 summit in Okinawa.

The proposed NMD, if successfully developed, will be capable of shooting down incoming nuclear missiles and will give the US a fundamental advantage over other nuclear powers.

However Washington insists the shield will not target either Russia or China, but is designed to counter the threat of rogue states such as North Korea and Iraq.

In a pre-summit meeting of G8 foreign ministers, the NMD program was called into question with concerns that the unproven system threatened to undermine the anti-ballistic missile (ABM) treaty.

But the issue was put into the background at the summit as Kim's surprise initiative figured prominently while US President Bill Clinton said he wanted more details of the offer before passing final judgement.