Malaysian Defence Minister Najib Razak has denied he had apologised to his Indonesian counterpart for recent incidents related to their joint border off Borneo island.

"Whatever it is, it didn't happen ... I myself did not apologise to the Indonesian minister of defence," Najib, also deputy prime minister, told reporters.

Indonesian Defence Minister Juwono Sudarsono on Wednesday said Najib had apologised after Malaysian warships and planes reportedly crossed into Indonesian territorial waters earlier this month.

They reportedly made the encroachment near an oil exploration area known as the Ambalat Block off Borneo, which has been a source of tension in the past.

"The Malaysian defence minister has expressed his apologies to me on the recent Ambalat incident and promised to warn his subordinates," said Sudarsono.

What was discussed

But Najib said he had talked to Sudarsono at a Southeast Asian defence ministers' meeting in Bali, Indonesia last week about forging "an understanding to avoid any undesirable incidents."

"He agreed that we should uphold the rules of engagement at the level of military leadership as well as on the ground," he said.

"In the case of Ambalat, it means that those who were commanding the ships must act maturely and not be emotional. That is what we agreed."

Najib said both countries had also noted bilateral political ties were "very good".

"So there's no reason that incidents such as Ambalat cannot be discussed between two countries that have a good relationship," he said.

"That was all. So the question of an apology did not arise."

The Ambalat block has been a source of tension in the past. Bilateral relations hit a low in 2005 when warships from the two sides brushed in the area.

Another dispute over the ownership of two islands ended in December 2002, when the International Court of Justice ruled they belonged to Malaysia.

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