Malaysia's long-ruling Umno party must place victory in a looming general election ahead of personal ambitions, and resolve its internal tensions "like a family", Prime Minister Najib Razak told party chiefs yesterday, as he sought to unify them at the start of its annual assembly.

In the closed-door briefing to top and grassroots leaders across all party wings, Datuk Seri Najib said a committee would look into "conflict resolution" to ensure a smooth campaign in the national polls that must be held by August, sources present told The Straits Times.

Umno started its five-day general assembly yesterday, with the traditional presidential briefing on the party's immediate challenges.

PM Najib said Umno has "three problem (relationships) - between Umno and Umno, between Umno and elected representatives, and between Umno and components" of the Barisan Nasional coalition, said an attendee at the briefing.

Mr Najib, Umno's president, called on members to compromise on election candidacy and have faith in a new selection methodology which has brought results in recent by-elections.

"Najib said those who have been candidates can make way for others as there are many ways to serve if the party remains in power," a source told The Straits Times.

Malaysia's biggest political party has overcome its crisis involving state fund 1Malaysia Development Berhad (1MDB), though the issue is far from settled outside the party.

With the general election likely within months, followed by Umno's internal polls, the party is facing intense jockeying for positions.

Its ranks of ambitious leaders want to be picked as candidates for the general election. There is also simultaneous jostling for posts ahead of its internal polls.

Second Finance Minister Johari Abdul Ghani told reporters that "all leaders must work together and compromise" as each seat could have only one candidate.

Umno vice-president Hishammuddin Hussein called on party leaders to focus on the election and not internal party positions. "It is important for them to put party above everything else. Facing an election, it's not just delegates in the hall who are important, but the public outside," he said.

In his briefing, Mr Najib admitted that mistakes were made in managing 1MDB - reiterating what he had said previously - but that the state fund he controlled had recovered.

He said two key developments launched by 1MDB which once chalked up RM51 billion (S$17 billion) in debt, the Tun Razak Exchange and Bandar Malaysia, would fetch a gross development value of RM40 billion and over RM100 billion, respectively.

PM Najib said this contrasted with the foreign exchange losses notched up by Malaysia's central bank in the early 1990s under the Mahathir administration. A recent Royal Commission of Inquiry had "corroborated that a RM31.5 billion loss (at the bank then) was real and not fabricated".

Mr Najib also sought to dispel doubts over whether Umno members should stand by him by attacking Tun Dr Mahathir Mohamad, his mentor-turned-nemesis, for being an iron-fisted dictator during his 22-year rule that ended in 2003.

Acting deputy president Ahmad Zahid Hamidi yesterday said the Umno-led Barisan Nasional (BN) coalition is keen to win back its supermajority in Parliament that it lost in 2008. "We want to command two-thirds of the parliamentary seats with an even bigger majority," he said at the joint launching of the annual meeting of Umno's three wings.

BN lost its two-thirds majority in the 222-seat Parliament in the 2008 and 2013 polls. It now has 132 seats - 16 short of the 148-ward supermajority.