Tokyo: Prime Minister Shinzo Abe on Wednesday promised at the start of his new term to revive Japan's economy so he can pursue "powerful diplomacy", but China's state media warned him to be wary about changing the pacifist constitution.

The lower house voted overwhelmingly to confirm 60-year-old Abe, with 328 votes against 73 for acting opposition leader Katsuya Okada. That was followed by an upper house poll which officially endorsed Abe as premier following
his sweeping election victory this month.

His new cabinet was largely unchanged with Taro Aso returning as deputy premier and finance minister, Fumio Kishida as foreign minister and Yoichi Miyazawa in the industry minister post.

Industry is a key portfolio that oversees Japan's nuclear power sector, as Abe looks to restart more atomic reactors
shuttered after the 2011 meltdown crisis at the Fukushima plant.

The only new face was Gen Nakatani, replacing Akinori Eto as defence minister after Eto declined reappointment in the
midst of a political funding scandal.

Nakatani, 57, headed the defence agency -- later upgraded to a ministry -- in 2001-2002.

On top of trying to kickstart the world's number three economy, Abe has vowed to pursue a nationalist agenda, including persuading a sceptical public of the need to revise the constitution.

He wants Japan's powerful military to have the power to come to the aid of allies such as the United States if US
forces are attacked.

The attempt to alter the charter, imposed by the US after the end of World War II, "is a historic challenge but it is
difficult to do", Abe told a news conference late today. His efforts have proved divisive at home and strained
already tense relations with China.

"Abe and his new defence minister... need to tread carefully," China's official Xinhua news agency said today.

"The two both advocate a stronger role for Japan's Self-Defence Forces (military), and the international community should keep a wary eye on them and constantly remind them not to go too far."

Relations, however, have begun to thaw after a more than two-year chill that Beijing blamed partly on Abe's provocative nationalism, including a visit to a controversial war shrine, and equivocations on Japan's wartime record of enslaving women for sex.

The prime minister's incumbent cabinet resigned en masse this morning, following the ruling coalition's victory in
December 14 polls that were billed as a referendum on Abe's economic growth blitz, dubbed Abenomics.

But many observers said the snap election was more likely aimed at fending off rivals before a ruling party leadership vote next year.