Indian scientists have completed final trials of a genetically modified (GM) variety of mustard and will submit a report to the government in a month, hoping to win over stiff opposition to make it the country's first commercial transgenic food crop.

A powerful farmers group close to Prime Minister Narendra Modi's Bharatiya Janata Party (BJP) is one of the biggest critics of GM crops and wants the government to stop all field trials saying they "will destroy the entire agrarian economy".

Allowing GM crops is critical to Modi's goal of boosting farm productivity in India, where urbanization is devouring arable land and population growth will mean there are 1.5 billion mouths to feed by 2030 - more even than China.

India imports about 60 percent of its edible oil needs at an annual cost of up to $10 billion - its third-biggest import item after crude oil and gold.

The new GM mustard offers India a chance to substantially reduce this import bill as it would be the highest-yielding oilseed in India, with yields 26-34 percent higher than the national average, said Delhi University's Deepak Pental, leading the research on the GM mustard.

Pental said recently concluded biosafety studies did not show any adverse allergenic, toxic or environmental impact.

"Oil and rapeseed meal of transgenic rapeseed have been consumed very extensively from 1996 onwards (outside India)," Pental told Reuters.

"If in spite of all this the material (GM mustard) is not released - that means we have fallen prey to whims and fancies of extreme ideologues."

Pental was referring to Bharatiya Kisan Sangh (BKS), or Indian Farmers' Union, which is affiliated to the ideological parent of BJP and opposes field trials of GM crops.

Last month BKS leaders met with some government scientists working on GM and urged them to stop all field trials, BKS national secretary Mohini Mohan Mishra told Reuters.

"The field trials will destroy the entire agrarian economy of this country because they have no clue about the long term impact," Mishra said. "They have been blinded by the western corporates and we will not let them commit this blunder."

"The scientists may complete field trials and submit reports but this will not translate into GM crops in Indian fields."

But in August last year, the Modi government resumed the field trials for selected GM crops with little publicity and in January, Maharashtra state led by the BJP gave the all-clear to trials of rice, chickpeas, corn and aubergine, as well as new varieties of cotton.

GM cotton developed by Monsanto Co and launched in India in 2002 helped transform the country from a net importer into the world's top fibre producer.