TOKYO (Reuters) -Japan's promised $550 billion in U.S. investments under the trade deal struck last month will be determined by whether they will benefit Tokyo too, the Asian nation's top tariff negotiator said on Tuesday.

Ryosei Akazawa's comments came after U.S. President Donald Trump, in an interview with CNBC on Tuesday, compared the promised Japanese investment to "a signing bonus that a baseball player would get," adding, "that's our money. It's our money to invest, as we like."

Washington struck a trade deal with Tokyo in July that sets a reduced rate of tariffs on Japanese goods, including autos, of 15% in exchange for a $550 billion package of U.S.-bound investments and loans.

Speaking to reporters on arrival in Washington, Akazawa described the financial package as "a commitment to invest in the U.S. where there are benefits for Japan as well", like for building a supply chain in economic security areas. 

"At the very least, we can't cooperate on anything that does not benefit Japan," Akazawa said in his first visit to the U.S. since the two countries reached the deal. 

Akazawa, however, added Trump will play a significant role in determining which projects to pursue as the money will be used for investments within the U.S., and his desire to build a supply chain will be reflected in them.

"It's not acceptable to ignore the U.S.'s intentions," he said.

During his visit, Akazawa will seek to press his U.S. counterparts for a quick implementation of the agreed cut to tariffs on auto imports from Japan.

He also told reporters he would seek an explanation from U.S. officials on the problem of "stacking", where goods can be affected by multiple tariffs.

A Federal Register attached to Trump's July 31 executive order that addressed tariff rates for many trading partners showed a "no stacking" condition applies to the European Union, but no such clarification was issued for Japan.

"It's different from what we've heard from the U.S. side," Akazawa said. "We'll request that the agreed-upon content be implemented."