Bangladesh's Prime Minister Sheikh Hasina will sign defence and nuclear energy deals worth $1.5 billion during a three-day visit to Russia which begins on Monday, the government announced.

Hasina flew out the Bangladeshi capital Dhaka on Monday at the head of a 54-member delegation to Moscow where she is expected to hold talks with President Vladimir Putin at his Kremlin offices on Tuesday.

Foreign Minister Dipu Moni told reporters a total of nine accords would be signed during the trip, including a $500 million credit agreement to help fund construction of Bangladesh's first nuclear power plant.

Moni also said Bangladesh would use Russian government credit to enable it to buy a range of defence equipment.

"The amount of the defence purchase deals that are going to be signed is one billion dollars," she told reporters in comments broadcast on Bangladeshi television.

The foreign minister did not give details of the equipment or of the terms of the repayment agreement.

But the mass-circulation Prothom Alo daily said fighter jets, helicopters, armoured vehicles, anti-tank missiles, automatic grenade launchers and radar equipment would all be included in the package.

A.N.M Muniruzzaman, an analyst at the Dhaka-based Institute of Peace and Security Studies, told AFP it was the biggest defence deal ever to be signed by Bangladesh which gained independence in 1971.

Bangladesh, one of the world's most impoverished countries, has been expanding its defence capabilities in recent years, building a new air base close to neighbouring Myanmar and adding new frigates to its navy.

In November 2011 it signed a deal with Russian state-owned nuclear agency Rosatom to build a nuclear plant in the northwestern town of Rooppur which will have two 1,000 megawatt reactors at a cost of up to $2 billion each.

Officials said Bangladesh needs the reactors because its natural gas reserves could run out within a decade.