Industry sources in Japan say the authorities have issued a formal request for information and that the document went to every major manufacturer of business jet aircraft.

The Mitsubishi MRJ regional jet is considered to be a front-runner in the competition.

Japan's government is under pressure to assist the local aerospace industry and the authorities want to procure an aircraft smaller than those now being used.

Japan's prime minister uses a Boeing 747 but a smaller aircraft, such as the MRJ90, might be preferable for trips to neighbouring countries such as China, South Korea and Taiwan.

Flightglobal's ACAS database lists Japan's government as having two 747-400 VIP aircraft, one built in 1990 and the other in 1991. These are operated by the Japan air self-defence force, which also has five Gulfstream IVs with an average age of 12 years, says ACAS.

The RFI has gone to a long list of aircraft-makers including Boeing, say the sources, one of whom says the authorities have also refrained from ruling out the 747 VIP for the competition.

But whether Japan's government goes ahead with a deal is unclear in light of the country's political situation and budget constraints.

The ruling Democratic party lost the upper house elections in early July and the government is grappling with its mounting debt.

Voters appear to have rejected the government's call to increase taxes and, as a consequence, the government may have to reign in spending.

Source: Flight Global