MANILA (REUTERS) - The United States said it has removed the Philippines from its piracy watch list after two decades following significant reforms put in place by Manila, raising prospects for increased trade and investment between the two allies.

The announcement, posted on the website of the Office of the US Trade Representative (USTR) on April 28, came during the first state visit of US President Barack Obama in the Philippines, the United States' oldest ally in the Asia-Pacific region.

In its statement, the USTR said the Southeast Asian country, which had been consistently on the watch list since 1994 and was first listed in 1989, had undertaken in recent years "significant legislative and regulatory reforms" to protect and enforce intellectual property rights rules.

Officials said the USTR decision would boost investor confidence in the Philippines. The US is among of the country's top three trading partners.

"Removal from the watch list creates the proper investment climate," said Ricardo Blancaflor, director-general of the Philippines' Intellectual Property Office.

"It reflects a vibrant rule of law system where foreign trading partners can feel secure in doing business in the country."

The USTR said in its statement significant challenges remained, but did not elaborate. It noted, however, that Philippine authorities had made "laudable" gains in enforcing intellectual property rights.

Senator Grace Poe said the country's removal from the piracy watch list was "a leap forward" in encouraging more foreign and domestic investment in the country.

"Removing us from the watch list gives us a better leverage in the international business community. We need to ensure that we encourage and increase that confidence with additional legislation that is business friendly," she added.