Sukhoi Civil Aircraft is understood to have delayed the start of flight trials of its Sukhoi Superjet 100 regional jet until May.

In a report to the Russian cabinet, minister for industry and energy Viktor Khristenko says the aircraft's maiden flight will take place in May rather than in April, as the manufacturer had previously indicated.

However, he maintains the aircraft should gain type certification under the domestic AP-25 airworthiness standards in 2008, with the European Joint Aviation Authorities certification due to be received next year.

The Russian government has given a considerable financial backing for the development of Superjet 100 designed to provide a replacement for the country's fleet of Tupolev Tu-134s.

To date, state budgetary funds allocated for the project have totalled almost 12 billion roubles (US$500 million). Around US$600 million has been attracted from other sources.