The official death toll stands at 131, but local media are reporting figures as high as 347.
'The corpses are starting to smell and we believe some people buried are still alive - that's why it's a critical time, ' Nugroho said.
Buildings still standing on the island have been weakened after Sunday's quake.
Rescue efforts have intensified to find people buried in rubble following the quake that shook Indonesia's Lombok island.
Evacuees in some encampments say they are running out of food, while others are suffering psychological trauma after the 6.9-magnitude quake, which struck just one week after another tremor surged through the island and killed 17.
Buildings still standing on the island have been weakened after Sunday's 6.9 quake that killed at least 131 people and a 6.4 quake on July 29 that killed 16.
Volunteers and rescue personnel have erected more temporary shelters for the tens of thousands left homeless on the island.
'We still need long-term aid, even though we have already received help from various (regional) governments, ' national disaster agency spokesman Sutopo Purwo Nugroho said.
Water - which has been in short supply due to a prolonged dry spell - as well as food and medical supplies have also been distributed from trucks.
The governor of the province that includes Lombok where the quake was centered, the military, the national search and rescue agency and regent of North Lombok issued different death tolls that ranged from 226 to 381.
A 5.9 magnitude natural disaster hit the Indonesian island of Lombok Thursday, according to the United States Geological Survey, an area already struggling to recover from a massive quake that hit Sunday.
Most people live in basic housing in small communities.
A field hospital has also been established near an evacuation centre catering to more than 500 people in the village of Tanjung.
Authorities are still searching through the rubble left behind on Lombok Island, still hoping to find survivors.