MANILA (Reuters) - U.S. companies are set to announce investments amounting to more than $1 billion dollars in the Philippines, United States Commerce Secretary Gina Raimondo said during an official visit to Manila on Monday.

The investments would be in areas like solar energy, electric vehicles and digitisation, she said, adding that U.S. companies were eager to do business in the Southeast Asian country.

Raimondo is in Manila for a two-day trade and investment mission on behalf of President Joe Biden. Her delegation includes top officials from companies like GreenFire Energy, Inc., Google Asia Pacific, Visa, United Airlines and KKR.

The White House in January said a trade mission would be sent to boost U.S. companies' contribution to key Philippine sectors including infrastructure, clean energy, critical minerals, agriculture and the innovation economy.

The Philippines and the United States are longstanding allies bounded by a 73-year old mutual defence treaty. Philippine President Ferdinand Marcos Jr has sought to deepen relations beyond defence cooperation to include economic partnerships.

"The U.S.-Philippine alliance is iron clad," Raimondo said at a joint briefing with Philippine officials. "It is sustained over 72 years, and we remain steadfast friends and increasingly, partners in prosperity."

(Reporting by Mikhail Flores, Karen Lema; Editing by Kanupriya Kapoor)