ASEAN must be united in voicing out issues especially related to disputes and its relations with the major powers, said Prime Minister Datuk Seri Najib Razak.

Without referring directly to the disputes or relationships involving any ASEAN country with the super powers, the Prime Minister in his address during the 28th and 29th ASEAN Summit, stressed the importance of centrality and unity for ASEAN to become a relevant and influential body.

"ASEAN must be able to speak as one voice, if there are conflicts, it will weaken ASEAN in any matter, especially on the question of disputes and its relationship with the great powers. And solidarity is very important," he told Malaysian journalists, here, Tuesday night.

Najib is leading the Malaysian delegation at the three-day summit, which began yesterday attended by 10 ASEAN leaders, including two new heads of state, namely Philippine President Rodridgo Duterte, and State Counsellor of the Republic of the Union of Myanmar, Aung San Suu Kyi.

"We have some challenges in getting a unified position, that is why it's important to stress ASEAN unity. We cannot afford to break ranks. If we can speak in one voice, we become much stronger because we speak on behalf of 630 million people," said Najib.

The Prime Minister said he also exchanged views and discussed the current situation in Davao City (in the southern Philippines).

According to media reports, at least 14 people were killed and 24 others injured when a bomb went off at a night market in Davao City on Friday.

Najib said Duterte also indicated to him that he wanted to make an official visit to Malaysia.

"He definitely wants to visit Malaysia, only that the date he asked for clashes with my visit to Germany," he said, adding that a new date would be fixed on the official visit by the President of the Philippines.