Philippine President Benigno Aquino Tuesday began a four-day visit to Japan that will see him court investment and seek support for his opposition to China's land reclamation in the South China Sea.

Aquino delivers an speech in parliament Wednesday, in which he is expected to focus on Beijing's construction of runways and other infrastructure on reclaimed islands, which has aggravated regional tensions and drawn US demands to stop.

The Filipino leader's visit to Tokyo comes less than a month after the two countries held their first joint military drill in modern history -- despite Japan's role as occupier of much of Asia during World War II.

Aquino's schedule also includes a meeting with Japan's emperor Wednesday and Prime Minister Shinzo Abe on Thursday, after speaking at an investment forum designed to lure potential business deals.

But politics will top the agenda.

Beijing has ramped up its land reclamation in the South China Sea at a dramatic pace in recent months, constructing man-made islands on top of reefs across a wide area to back up its territorial claims.

China insists it has a right to control nearly all of the South China Sea, including waters near the coasts of the Philippines, Vietnam and other Asian neighbours, which have competing claims to parts of the waters.

The US has pressed Japan to help its efforts to send military planes and vessels to survey the sea to maintain the right to free navigation.

Last week US Defense Secretary Ashton Carter met his Philippine counterpart Voltaire Gazmin. He reiterated that Washington's pledge to defend the island nation remains "ironclad" and called for an end to land reclamation.

The Chinese military last month ordered a US Navy P-8 Poseidon surveillance plane to leave an area above the disputed Spratly islands in the South China Sea.

But the American aircraft ignored the demand and said it was flying in what US officials consider international airspace.