By Elias Biryabarema

KAMPALA, Sept 21 (Reuters) - Uganda's veteran President Yoweri Museveni got the formal go-ahead from his party to stand again in elections next year, setting him up for a possible tough confrontation with ally-turned-adversary, former prime minister Amama Mbabazi.

Museveni, 71, has already dominated the east African nation for nearly 30 years, with a rule bolstered by economic growth, an often divided opposition and control of the security services.

But analysts say Mbabazi - the ruling party's former secretary general who is now hoping to stand as an opposition candidate - could be the president's strongest challenger yet.

Mbabazi, who was seen as a kingmaker in Museveni's government before he was sacked as prime minister in 2014, originally stood against Museveni to get the ruling National Resistance Movement's presidential nomination.

But he dropped out of that race in July, accusing officials of frustrating his bid.

Mbabazi then joined an opposition coalition, The Democratic Alliance, where he is in a tight race with three-time presidential challenger Kizza Besigye to secure the alliance's ticket.

The government media centre said Museveni had promised to improve living standards and "eradicate corruption in the country," after securing his party's nomination on Sunday.

Museveni, a key western ally, has been credited with returning economic stability to Uganda after years of turmoil.

But his critics have accused him of failing to check runaway corruption and of using security forces to harass opposition supporters during elections.

The opposition says it suspects Museveni is grooming his son, Kainerugaba Muhoozi, to succeed him.

The president regularly denies having any such intention and dismisses the other charges against him.

Presidential and parliamentary polls are scheduled between February and March next year. (Reporting by Elias Biryabarema; Editing by George Obulutsa and Andrew Heavens)