(Adds rebels burn heavy equipment in Samar, deail on damage)
MANILA, Dec 10 (Reuters) - Philippine rescue teams were struggling on Wednesday to reach upland communities on an eastern island which took the brunt of a typhoon at the weekend amid security fears in an area known as a hotbed of Maoist insurgents.
Typhoon Hagupit destroyed nearly 16,500 houses and damaged more than 33,100 on the island of Samar before making its way slowly across the country. It has since been downgraded to a tropical storm and on Wednesday was headed for southern Vietnam.
The national disaster agency said 11 people were killed as the storm churned across the central islands and the southern tip of the main island of Luzon. The Red Cross has confirmed 25 deaths. The health ministry and Red Cross were checking reports that nearly 40 people died. Nearly 500 people were injured.
"We're trying to reach upland villages ... but landslides and fallen trees make it difficult," Richard Gordon, head of the Philippine Red Cross, told Reuters.
"We expect casualty figures to increase as we get more information on the ground."
The Red Cross has rented a helicopter to survey upland areas while Red Cross and government officials said they were worried communist rebels might try to steal communications equipment and portable generators.
New People's Army guerrillas have been fighting the government for 45 years and have a strong presence in some rural communities.
Military spokesman Colonel Restituto Padilla said while the communist rebels were not known for kidnappings, unlike the Muslim Abu Sayyaf militants in the south, security forces were protecting relief workers.
"We know the risks so we escort the people involved in humanitarian work, especially if there are international aid agencies there. We don't want any untoward incident."
On Wednesday, about 30 rebels attack a South Korean company, Hanjin Heavy Industries and Construction Co. Ltd, working on a U.S.-funded road in Eastern Samar and burned two trucks and a backhoe, the army said.
"They took advantage of the situation," Padilla said. "We are focused on humanitarian mission in the north and we have minimal presence there."
Alexander Pama, executive director of the national Disaster Risk Reduction and Management Council, said more than two million people were "affected" by Hagupit and about 1.7 million were evacuated.
About 800,000 jobs and livelihoods were disrupted or lost, according to the International Labour Organization.
Pama said damage was estimated at 2.5 billion pesos ($56.04 million). About 56,000 metric tonnes of rice, corn and other crops were lost.
But the damage was nowhere near that wrought last year by Typhoon Haiyan, which destroyed or damaged more than a million homes and killed, or left missing, more than 7,000 people. (Reporting By Manuel Mogato and Neil Jerome Morales; Editing by Nick Macfie and Robert Birsel)