The recent weakness of the Japanese yen is mainly driven by speculative moves, the head of the country's biggest business lobby Masakazu Tokura said on Monday, adding that debating monetary policy based on such moves was inappropriate.

"Discussing the direction of monetary policy based on speculative yen moves isn't appropriate," said Tokura, who heads the powerful Keidanren business lobby.

His comments followed a renewed slide in the yen against the dollar on prospects of aggressive U.S. interest rate hikes. The Japanese unit hit a fresh 24-year low of 140.80 yen per dollar on Friday.

"Even if the Bank of Japan's monetary policy is tweaked a little and negative interest rates are put at 0% or 0.5%, it won't change (the weak yen trend)," Tokura told a news conference.

Finance Minister Shunichi Suzuki had warned after the yen's slide to its low on Friday that Tokyo will take "appropriate" action, signalling the chance of intervention to address market volatility.

Investors, however, have taken the government's verbal warnings in their stride as the yen's current weakness reflects economic fundamentals driven by monetary policy divergence and interest rate differentials between Japan and the United States.

The yen on Monday still hovered near its multi-decade low against the greenback, last trading at 140.44 yen per dollar. (Reporting by Miho Uranaka; Writing by Daniel Leussink; Editing by Hugh Lawson)