However, Kampong Kuala Balai is currently uninhabited due to factors such as migration to other villages and employment opportunities elsewhere, leading to a decline in its once-thriving community.

[6] Kampong Long Pelai is rich in natural resources, with the surrounding land featuring sago palms and other forest products, while the waters provide opportunities for fishing.

[7] Originally a small fishing community, Kuala Balai was designated as the headquarters of the Belait District in September 1907, a status it maintained until 1929 due to a significant increase in oil prospecting licenses issued by the Bruneian government.

[8] Kampong Kuala Balai is believed to be the original settlement of the Belait people, with some later relocating to cultivate rice or pursue employment in government, commercial businesses, and oil companies.

[9] Over time, younger generations began moving to Kuala Belait and Seria, causing the village's population to decline sharply from 150 in 1955 to fewer than 100 by 1959.

He expressed hope for the establishment of a primary school in Kuala Balai and the appointment of a religious instructor to serve as the Imam and lead the village's Friday prayers.

During the Japanese occupation, the military introduced modern machinery, specifically generators, which the villagers utilised to enhance their sago processing capabilities.

A survey conducted in 2010 revealed several abandoned sago processing factories, left in disrepair and serving as a stark reminder of the industry's disappearance.

[citation needed] As of 2021, the mukim consisted the following villages: The Mumong bypass is approximately a 20-minute drive from the settlement on the Belait River's banks, and the freshly repaired gravel route should be accessible to any vehicles with a typical road clearance.

[15] A voyage required six hours of arduous rowing in a longboat, and bigger cargo-carrying boats used to travel up the Belait River when the population was large enough to maintain a school.

[16] Islam began to flourish in Kuala Balai during the 19th century when Pengiran Anak Tengah was appointed as the Sultan of Brunei's representative to manage administrative affairs in the Belait District in 1883.

The mosque was led by Imam Radin Muhammad Salleh, who came from Pontianak, Kalimantan, and was brought to the village by Pengiran Anak Hashim from Benoneh, Sabah.