US President Donald Trump unveiled a US$10 billion (HK$78 billion) investment by Apple supplier Foxconn to build a plant in Wisconsin.

The businessman-turned-president made the announcement side by side with the Taiwanese tech giant's CEO Terry Gou, as he tried to show his "America First" economic rhetoric is making a difference.

Trump said the plant - which will make LCD panels - will create at least 3,000 jobs in the midwestern state, and was quick to stress he played a role in making the deal happen.

"If I didn't get elected, he would not be spending US$10 billion," Trump said, thanking Gou for his "faith and confidence in the future of the American economy."

Foxconn said the plant could eventually bring more than 13,000 new jobs to Wisconsin, with Gou adding it was the first in a series of facilities the company would build in several US states.

"Wisconsin offers a talented, hard- working workforce, and a long track record in advanced manufacturing, all of which presents an extraordinary opportunity," the Taiwanese tycoon said.

Manufacturing in the US would allow Foxconn to better serve its customers, including "iconic" American technology companies, Gou added.

Trump allies said Gou had spotted an abandoned factory and suggested it be used, and Trump personally met Gou in April to push the deal forward.

Trump has made returning manufacturing jobs to America's heartland a key plank of his domestic policy.

The investment is a double win for Trump, burnishing his reputation as a job creator and putting those jobs in a key battleground state, which he won in 2016 by a single percentage point.

The White House did not say what tax incentives were offered to entice Foxconn, but local media reported a tax break package of about US$3 billion.

Foxconn, also known as Hon Hai, has been mulling moving to the US since early this year to have better control over distribution networks.

The firm is the world's largest contract electronics maker and is best- known for assembling products for major companies, such as Apple and Sony.

It employs about a million workers at its factories across China and has operations in over 10 countries.

In the US, it has a plant in Virginia for packaging and engineering, employing over 400 people. It said it will invest $40 million in a plant in Pennsylvania to build precision tools and develop a robotics program.

AGENCE FRANCE-PRESSE