Prime Minister Najib Razak yesterday urged dissenters in Umno to set aside differences and return to the fold, but he also warned that not doing so would mean rejecting the party leadership's decision.

The carrot-and-stick approach taken by Datuk Seri Najib in his winding-up speech at the close of the five-day annual party congress was greeted with thunderous applause and cheers from the 2,700 delegates in the hall.

"I choose to be the bigger person to open the door and offer goodwill to everyone so we can unite and solidify the bonds of Umno," he said.

Reject it, Mr Najib cautioned, and it would no longer mean "a personal attack" but shunting aside the wishes of the top Umno leadership.

His speech was directed at party dissenters led by deputy president Muhyiddin Yassin and one of the three vice-presidents, Datuk Seri Shafie Apdal. Both men have been critical of Mr Najib's handling of two funding scandals and were sacked from the Cabinet in July. They were on stage with other leaders and looked uncomfortable.

Mr Najib echoed his opening speech on Wednesday, ending his speech yesterday with: "There shall be no retreat, no surrender!"

Said Professor Mohamed Mustafa Ishak from the National Council of Professors: "Najib has made it clear that he will continue as prime minister and Umno president regardless. He will not withdraw, he will not go on leave."

Mr Najib in his speech reminded delegates of the Malay way of politely handling disputes, and asked the party to start preparing for the next general election, due by 2018.

"We must make preparations ...We need to clear our heads," he said. He also asked them to work harder to register new voters.

During the five-day assembly, delegates had largely stuck to the same rhetoric of pledging allegiance to the party leadership.

The consistency in the speeches followed Mr Najib's stern message on Wednesday calling on members to unite and stay loyal to him.

Yesterday, he referred to the Malay race and culture to remind delegates of the importance of staying loyal and respecting leaders.

Tan Sri Muhyiddin and Mr Shafie, who are being investigated by the party's disciplinary board for holding a political rally attacking Mr Najib last Monday, have maintained that they are party men raising issues for the sake of Umno.

"This is not a war or a fight," Mr Muhyiddin told reporters after the assembly.

"After this, I would want to see what are the steps taken to tackle the issues that I've brought up," the former deputy prime minister said.

Mr Najib has been fending off critics over the massive debts of state investor 1Malaysia Development Berhad (1MDB).

Yesterday, he urged delegates not to blindly believe reports on 1MDB, calling it "a perception war".

Mr Najib, who is also finance minister and chairman of 1MDB's advisory board, has also drawn flak for receiving a mystery donation of some US$680 million (S$960 million) in 2013. Malaysia's anti-graft agency is probing the matter and has classified the money as a donation from the Middle East.

The introduction of an unpopular goods and services tax in April and the weakening ringgit have made Malaysians rather unhappy.

Mr Najib, assuring delegates that Umno is committed to alleviating the people's economic burden and raising living standards, yesterday announced train fare discounts for civil servants, senior citizens and students.