Japan's embattled prime minister insisted Tuesday he would stay in his job despite press speculation he may step down ahead of upper house elections next month.

Centre-left leader Yukio Hatoyama, who took power in a landslide election last August, has seen his approval ratings battered by a row over a US military airbase on the southern island of Okinawa.

His U-turn decision to keep the unpopular base on Okinawa despite strong local opposition has caused a split in his three-party coalition, with the small, pacifist Social Democrats bolting the government on Sunday.

Newspaper front-pages Tuesday said Hatoyama faced growing calls from within his Democratic Party of Japan (DPJ) to quit.

The premier on Monday night met with political heavyweight Ichiro Ozawa, the DPJ secretary general who is often described as the party kingmaker and power behind the prime minister's throne.

Hatoyama, who was expected to meet Ozawa again later Tuesday, signalled that he wanted to stay on in his post, telling reporters in the morning: "I want to cooperate with him (Ozawa) to tackle national challenges."

Local media, quoting party sources, said the two would discuss whether Hatoyama should resign ahead of the election for the upper house of parliament on July 11.

The premier then left for a day-trip to southern Japan to offer support to cattle farmers suffering from an outbreak of foot-and-mouth disease, which has sparked a costly cull of infected animals.

The premier's right-hand man, Chief Cabinet Secretary Hirofumi Hirano, ruled out Hatoyama's resignation.

"I think it is unreasonable in the first place that people should talk about whether the prime minister should stay or leave," Hirano told reporters.

Deputy Prime Minister and Finance Minister Naoto Kan - seen as among the top candidates to step into Hatoyama's shoes should the premier resign - also backed Hatoyama.

"I have been saying I want the prime minister to fulfil his duties for the full four-year tenure and my thinking hasn't changed," he told reporters.

But Kan also said Hatoyama's handling of the Okinawa issue had damaged the government, with media polls pointing to support for the prime minister dropping below 20 percent.

"I believe almost everyone in the DPJ shares the view that we are in a very severe situation," he said.

Transport Minister Seiji Maehara, another possible contender for the premier's job, said support for the DPJ had diminished, in part because both Hatoyama and Ozawa have been embroiled in political funding scandals.

"It's a fact that public support is declining due to the problem of the prime minister's leadership and the funds issue of the two leaders," he said.

Maehara also said the Okinawa row had hurt the government, after Tokyo and Washington agreed last week to keep the US Marine Corps Air Station Futenma on Okinawa in the teeth of mass protests.

But he also stressed the need for continuity in leadership, saying: "It's problematic if the prime minister is replaced frequently, so I want the prime minister to reflect on his past conduct and work hard."

Hatoyama is Japan's fourth premier in four years.

Shizuka Kamei, the minister of financial affairs who is leader of the DPJ's remaining coalition partner, the tiny People's New Party, said: "I'll support him (Hatoyama) with my utmost efforts."

- AFP