* BJP forecast to win most seats, but may need partners
* Modi may rely on support of veterans for coalition deal
* Party VP say such disagreements normal in run-up to vote
By Shyamantha Asokan
NEW DELHI, March 24 (Reuters) - India's Hindu nationalist opposition party saw internal spats deepen on Monday over the choice of candidates for next month's election, highlighting one of the hurdles its leader Narendra Modi faces in his attempt to become prime minister.
Modi needs all the support he can get from fellow members of the Bharatiya Janata Party (BJP) to secure the top job. The party is forecast to win the largest single chunk of seats in the election, but will likely rely on striking deals with coalition partners to form a majority.
Modi's rise in the BJP and personal magnetism has grated with some of the party's old guard, who say he is replacing the party's tradition of internal democracy with one-person rule. Critics outside the party often accuse the three-times chief minister of the state of Gujarat of autocratic tendencies.
Indian stock markets have rallied in recent months, partly on hopes that Modi will become prime minister, given his promises to be a business-friendly leader who will get the country out of its economic downturn.
However, Jaswant Singh, a senior BJP leader and former finance minister, quit the party on Monday after he was denied a seat to contest in the elections starting on April 7. BJP veteran L.K. Advani was last week convinced to run for a seat in Gujarat despite wanting to stand elsewhere.
"This NaMo NaMo drama, and the style of decision-making that is happening nowadays ... is full of arrogance," Singh told reporters on Monday, using the nickname for the BJP candidate that is favoured by his supporters.
"It will be destructive for the party."
The move to stop Singh being a candidate has drawn criticism from BJP leaders such as Sushma Swaraj, the party's leader in the lower house of parliament.
Modi has topped many large opinion polls this year as voters' most popular choice for prime minister in the world's largest democracy. However, the BJP is unlikely to emerge with a majority and Modi could well need support from its top brass during coalition negotiations.
The BJP and its allies are forecast to win around 210-230 seats in India's 543-seat parliament, according to the polls. The ruling Congress party faces an uphill struggle to be re-elected due to public anger over a string of corruption scandals and the economic slowdown.
"He is putting his own team in place and trying to marginalise senior leaders," said Neerja Chowdhury, a political analyst and former political editor of the Indian Express newspaper.
"For Modi to insist on having his way is politically surprising. At this stage, he should be trying to give signals that he is willing to be a team player."
Some BJP leaders denied Advani had been strong-armed into running in Gandhinagar, the capital of Gujarat, and said disputes over candidates were normal in the run-up to an election.
"This kind of development will always take place," BJP vice-president Mukhtar Abbas Naqvi told Reuters. "You can't judge the party and the whole election by these kinds of developments." (Additional reporting by Malini Menon in NEW DELHI; Editing by Frank Jack Daniel and Alison Williams)