NILAI - Malaysia's Inspector-General of Police (IGP) Khalid Abu Bakar has denied reports that a Malaysian militant who helped finance the ongoing siege by extremists on the southern city of Marawi has been killed in the fighting.

Media reports quoting the Philippine military had earlier on Friday said that Mahmud Ahmad was wounded in the fighting in Marawi last month and died on June 7 of his wounds.

"Dr Mahmud is still alive and fighting in Marawi (on Mindanao island)," Khalid was quoted saying by The New Straits Times on Friday evening.

Malaysian counter-terrorism authorities have said they could not confirm Mahmud Ahmad's demise as his body has not been found. However, they confirmed that Mahmud has been raising funds for the terror group.

Khalid on Friday also rejected speculation that many of the terrorists in Marawi are Malaysians, saying only less than 20 Malaysians are believed to be fighting there.

"We are still trying to determine the exact number of Malaysians involved in the terror activities in Marawi," he was quoted saying.

General Eduardo Año had told The Straits Times, citing intelligence shared by foreign counterparts, that Mahmud is suspected of channelling more than 30 million pesos from the Islamic State in Iraq and Syria (ISIS) group to acquire firearms, food and other supplies for the attack in Marawi.

It was previously reported that the university lecturer-turned-militant, who is highly regarded by fighters battling government security forces in the southern Philippines, had assumed a leadership role among Maute militants in the region with links to ISIS.

Omarkhayam Maute, who with his brother Abdullah formed the group that supplied the bulk of gunmen who stormed Marawi a month ago, is also believed to have been killed.

Lieutenant-Colonel Jo-Ar Herrera, spokesman of Task Force Marawi, told reporters they had validated information on Maute's death.