* Reliance plans 5G push to take on rivals in India

* Partners with Google to make new phone

* Intends to launch new consumer goods business

* Ambani says children taking leadership roles, being mentored

NEW DELHI, Aug 29 (Reuters) - India's telecom leader Reliance said on Monday it is working with Alphabet Inc's Google to launch a budget 5G smartphone as it laid out a $25 billion plan for introducing the next-generation wireless services within two months.

Speaking at the company's annual general meeting, Reliance Chairman Mukesh Ambani said Jio's 5G network will be the world's largest, launching in main cities including New Delhi and Mumbai before being expanded across India by December next year.

Ambani, one of India's richest men, said only that the phone being developed with Google would be "ultra-affordable". The cheapest 5G phones retail for around $150 currently in India, where around 700 million people don't have a smartphone.

"To take the 5G mass market, a sub-$100 phone is imperative and Jio is rightly positioned to bring 5G to the masses," said Neil Shah, vice president of research at Counterpoint.

5G data speeds in India are expected to be about 10 times faster than those of 4G, with the network seen as vital for emerging technologies like self-driving cars and artificial intelligence.

Reliance's 5G plans throw down the gauntlet to rivals Bharti Airtel and Vodafone-Idea in the world's second biggest mobile market. Shares in Airtel and Vodafone closed down 1.3% and 3.3% respectively in a weak Mumbai market where Reliance also slipped 0.78%.

Jio, India's biggest mobile carrier with more than 420 million customers, snapped up airwaves worth $11 billion in a $19 billion 5G spectrum auction earlier this month.

The aggressive 5G strategy builds on Jio's playbook of disrupting India's telecoms market having sparked a price war in 2016 when it launched cheap 4G data plans and free voice services, and later a 4G smartphone costing just $81, again in partnership with Google.

SUCCESSION, CONSUMER PLAY

With a market value of $220 billion, Ambani's business empire spans telecoms, retail, oil-and-gas and new energy.

He said he was among those mentoring his children on a daily basis as they begin to take the reins at the company, with Akash and Isha assuming leadership roles in Jio digital and in retail respectively, and Anant joining the new energy business.

Akash, 30, was also named chairman of the board of Reliance's telecom unit in June.

Ambani senior added that he would provide an update next year on IPO plans for Reliance's digital and retail units, which raised around $22 billion from global investors such as KKR & Co Inc and Silver Lake in 2020.

Reliance also announced the long-awaited integration of its grocery shopping app JioMart with investor-partner Meta Platform Inc's WhatsApp, allowing users to shop via the messaging app.

Separately, Isha Ambani said Reliance will launch a new consumer goods company this year, without giving details.

Reuters exclusively reported in May that Reliance has plans to acquire dozens of grocery and non-food brands to build a $6.5 billion business to challenge foreign giants like Unilever (Reporting by Munsif Vengattil in New Delhi; Additional reporting by Bengaluru newsroom, Abhirup Roy; Editing by Aditya Kalra, Kirsten Donovan)