US President Barack Obama wasted no time in courting China's new President Xi Jinping Thursday, calling him within hours of his elevation, and then pressing him on cybercrime and North Korea.

Obama, beginning his second term as Xi embarks on his first, congratulated his new opposite number in the crucial US-China relationship, and announced the dispatch of two senior cabinet lieutenants to Beijing shortly.

The US president had a cordial yet sometimes frustratingly formal relationship with Xi's predecessor Hu Jintao, and his decision to reach out quickly to the new Chinese leadership may be a sign of intent.

The White House said Obama congratulated Xi on his new position and promised regular high-level engagement on economic and security challenges on which Beijing and Washington have been increasingly at odds in recent months.

"The president highlighted the threat to the United States, its allies, and the region from North Korea's nuclear and missile programs," and sought close coordination with China on the issue, a statement said.

Earlier this week, Obama said he detected increasing frustration in Beijing with its troublesome ally, following Pyongyang's third nuclear test and inflammatory rhetoric towards Washington and Seoul.

Obama also raised with Xi the importance of addressing cybersecurity threats which he said, diplomatically, represent "a shared challenge."

In an ABC News interview this week, Obama was more blunt, saying some Internet-borne attacks on US corporations, infrastructure and government from China were state-sponsored, and pledged to raise them at the highest levels.

Shortly after Obama spoke to Xi, officials said Treasury Secretary Jacob Lew would travel to Beijing next week to discuss the vast and complicated relationship between the world's two largest economies.

US Secretary of State John Kerry will follow Lew to Beijing in mid-April, on a trip also including South Korea and Japan, as he seeks to lock in gains from an Obama administration first-term diplomatic and military pivot to Asia.

China's state Xinhua news agency said that Xi told Obama that "China and the United States have enormous common interests, but also differences."

"He emphasized that as long as the two sides follow the spirit of mutual respect, openness and tolerance, China and the United States will be able to achieve more" and turn "the Pacific into an ocean of peace and cooperation."

Beijing has viewed Obama's pivot of diplomatic and military resources towards Asia with concern, and chafed as Washington has supported the idea of a regional code of conduct on maritime disputes wanted by its allies.

Xi also underlined China's principles on cyber security and North Korea, Xinhua said without giving further details.

US officials, long frustrated at China's stance on North Korea, for which it is a dominant source of oil and food, were encouraged that China helped draft a new UN resolution condemning Pyongyang's nuclear test last month.

But new tensions have erupted over a report by US security firm Mandiant which said a unit of China's People's Liberation Army had stolen hundreds of terabytes of data from at least 141 organizations, mostly in the United States.

Obama has complained that industrial secrets worth billions of dollars are being stolen by cyberhacking, and top US officials have sharpened public warnings to China on the issue.

China denies the state is behind foreign cyberespionage and says it is also a victim of the new form of Internet-based warfare.

State Department spokeswoman Victoria Nuland was asked about China's suggestion of talks on cyberhacking, and said Washington wanted to ensure such an approach would not close off the Internet in a way that would harm freedoms.

The Treasury said Lew, who replaced Timothy Geithner, would discuss "efforts to level the playing field and create new opportunities for US workers and businesses."

The former White House chief of staff and deputy secretary of state will also look for common ways for Washington and Beijing to expand economic growth during his trip, officials said.

No plans for Xi and Obama to meet in person were announced Thursday. Their first likely opportunity would be at the G20 summit in St Petersburg in September.

The two did meet in the Oval Office when then vice president Xi got a red carpet welcome in Washington in February 2012, in the knowledge that he was China's leader-in-waiting.