A bitter family feud pitting father against son within the ruling Samajwadi or Socialist Party in the state of Uttar Pradesh could potentially give Prime Minister Narendra Modi's party an edge in crucial state polls expected in the first quarter of the year, analysts say.

Uttar Pradesh Chief Minister Akhilesh Yadav, 43, has been fighting his 77-year-old father Mulayam and uncle Shivpal, 61, for control of the party for months.

The younger Yadav appeared to have wrested control of the party after being chosen as party chief by a majority of legislators at a national convention on Sunday over his father Mulayam, a former wrestler turned politician.

"Sometimes to protect the ones you love, you must make the right decision. What I did today was a tough decision but one that I had to take," said Mr Akhilesh. Just last week, he was expelled from the party for six years by his father and then reinstated following an outcry.

But his father - an astute politician who single-handedly built up the Samajwadi Party over three decades - and his supporters have termed the appointments made at the convention as "illegal". The two sides are also fighting over the party's election symbol, a bicycle.

Uttar Pradesh is India's most populous with over 200 million people and also politically important with 80 MPs, the largest representation of any state in the Upper House of Parliament. Politics in the state has been dominated by regional players like the Samajwadi Party and India's Dalit leader Mayawati, the head of the Bahujan Samaj Party, with national parties Congress and Mr Modi's Bharatiya Janata Party (BJP) maintaining a secondary presence.

While the Congress is still struggling to recover from its 2014 defeat, Ms Mayawati has maintained a low-key profile amid revelations from the Enforcement Directorate that over 1 billion rupees (S$21.3 million) had been deposited in party accounts after the recent demonetisation. She has denied the money is black money.

Mr Modi at a massive rally yesterday maintained the BJP was the only option for the state. "Today, one party wants to save its cash, another party wants to save its family; only BJP wants to save UP," he said. "There is only one option for Uttar Pradesh and it is the BJP."

While weakening of regional players in the state could provide an opening for the BJP, analysts also said much depended on how the family drama plays out in the coming weeks, and if the Samajwadi Party entered into a tie-up with the Congress party led by the Gandhi family.

A tie-up could consolidate Samajwadi's key minority voters who are now divided. Over the last five years, the party, with its core support among the minority Muslims and Yadav farming community, has seen the emergence of multiple power centres. Some supported Mr Akhilesh who was often publicly rebuked for poor governance by his father and uncle Shivpal - two other power centres. Mr Akhilesh has, in turn, accused his elders of not allowing him to make decisions.

"If the Samajwadi Party splits down the line, that would automatically work to the advantage of the BJP as it would split the minority votes. But if Akhilesh is able to retain the support base, which a lot of people believe will happen, he could well ride on a sympathy wave," said Dr Sandeep Shastri, pro vice-chancellor of Jain University in Bangalore.

Said Uttar Pradesh's Planning Commission member and political analyst Sudhir Panwar: "The Samajwadi Party suffered from multiple power centres and it hampered work in government and the public image. Now that confusion is removed, however unceremoniously. It will brighten their prospects in the elections."