Japan will push to resolve a decades-old dispute with Russia over a cluster of small islands at a leaders' summit this week, although the bleak outlook for progress may mean the talks focus more on growing economic ties.

Any concession Japanese Prime Minister Taro Aso can draw from Russia on the islands would be a boost for the unpopular leader. With an election due this year, support for Aso's cabinet has fallen below 10 percent, an opinion poll showed on Sunday.

Aso will bring up the row, which has blocked the signing of a peace treaty ending World War Two, when he meets Russian President Dmitry Medvedev on the island of Sakhalin on Wednesday, a Japanese official said.

His one-day visit will be the first to Sakhalin by a Japanese leader since it was seized by the then Soviet Union, along with a chain of neighbouring islands, in the last days of World War Two.

Japan still lays claim to the group of islands, known in Russia as the Southern Kuriles and in Japan as the Northern Territories, scattered near rich fishing grounds close to Russian oil and gas production regions.

Analysts say hopes of a breakthrough are slim without a bold new proposal from Japan, given Russia's unwillingness to budge.

The Oriental Economist newsletter reported that Aso would offer a new proposal on the islands during the trip, but a foreign ministry official suggested such a move was unlikely.

"Unless Japan changes tactic, there will be no progress on the issue, and there haven't been any signs that Japan is coming up with a new approach on the issue," said Toshihiko Ueno, a professor of Russian politics at Sophia University in Tokyo.

A senior Kremlin source said that, while the territorial issue would be discussed, "they are not viewed (by the Kremlin) as a top item on the agenda".

The islands, the closest of which is just 15 km (9 miles) from Japan's northernmost island of Hokkaido, still stir public sentiment in Japan.

The talks could touch on a recent spat in which Japan called off a humanitarian aid mission to the islands after Japanese officials were asked to submit disembarkation cards.

Aso and Medvedev will also discuss growing economic ties, which have flourished in recent years despite the island spat.

Two-way trade has grown more than fivefold since 2002. Major investors include carmaker Toyota Motor Corp, which opened its first plant in Russia in 2007.

Russia is also keen for Japanese investment to develop its Far Eastern regions, while resource-poor Japan has been eager to tap Russia's booming oil and gas industries to reduce its reliance on the Middle East for its energy needs.

Aso will launch production at the Sakhalin-2 oil and gas project to produce liquefied natural gas (LNG), a venture in which Japan's Mitsui & Co and Mitsubishi Corp are minority shareholders.

The project has a rocky history, but analysts said Japan was willing to put the controversy behind it for the sake of securing its future energy needs.