Bangladesh’s main opposition BNP on Tuesday launched a long march demanding a “due share” in the waters of the Teesta river, raking up the contentious issue that has been a major irritant in ties with India.

A convoy of 50 minibuses and cars carrying leaders of Bangladesh Nationalist Party (BNP) began the march towards the Teesta Barrage bordering Lalmonirhat district where the Teesta river makes its way into Bangladesh from India.

“Our long march is not a programme against the government. Rather, we are holding the programme for ensuring people’s due share of Teesta water... BNP is waging the campaign for Teesta’s water as it is a life-and-death question for Bangladesh,” BNP’s acting secretary general Mirza Fakhrul Islam Alamgir said at a brief rally before the start of the march from Uttara area here.

He said the demonstration is aimed at enabling Prime Minister Sheikh Hasina’s government to take a stronger stance to realise the justified demands for Teesta water and other common rivers while making the international community aware of the miseries Bangladeshis have to suffer.

The BNP demonstration came as officials said massive withdrawal of waters upstream of the Teesta has severely affected the major Boro crops particularly in four northwestern districts, often called the granary of Bangladesh.

They said the water flow in the Teesta river has dropped to 650 cusecs from 3,500 cusecs around this time last year.

During his last month visit to New Delhi, Bangladesh’s foreign secretary Shahidul Haque expressed concern about the drastic fall in the flow of water of the Teesta.

However, political analysts say Khaleda Zia-led BNP is using the march as an opportunity to make visible its presence in the political arena as its boycott of the January 5 elections largely eroded the morale of party activists and supporters as it lost a chance of becoming a strong opposition in the Parliament.

Bangladesh and India were set to ink a deal on the issue during Prime Minister Manmohan Singh’s Dhaka visit in September, 2011, but West Bengal Chief Minister Mamata Banerjee reportedly raised objection over the proposed quantum of waters saying it would harm her state.

She also scrapped her tour to Dhaka accompanying Prime Minister Singh.

Senior BNP leader Hannan Shah on Monday said the party was temporarily enjoying a “vacation or hibernation” while addressing a discussion.

BNP, in a statement earlier, said the party leaders would stage six street side rallies on its way to the Teesta Barrage site and conclude the march holding another rally at Dalia area of Lalmonirhat.

State Minister for Home Affairs Asaduzzaman Khan on Monday said the government would extend its support to the long march provided BNP holds the demonstration peacefully.

However, Mr. Khan issued a note of warning against any activity to disrupt peace, saying stern legal actions would be taken if any such situation arose during the demonstration.

The water of the Teesta is crucial for Bangladesh, especially in the leanest period from December to March when the water flow comes down to less than 1,000 cusecs from 5,000 cusecs.

Drastic fall in water flow of the Teesta during the lean season, especially in February and March, seriously hampers irrigation in Bangladesh.

Sources in Joint Rivers Commission (JRC) said the flow on the river has weakened significantly in the last 24 years.

Officials said Teesta water is vital for irrigating around 6.4 lakh hectares of cropland in Bangladesh’s northwestern part during the lean season.

Riverine Bangladesh is criss-crossed by dozens of major rivers with 54 originating from India with only one bilateral treaty signed on the sharing of Ganges water in 1996.

Indian leadership earlier repeatedly assured Dhaka of signing the deal as early as possible after ensuring the consensus of all stakeholders.