A grab from a Greenpeace video issued on October 6, 2015 shows fires burning around the edge of the Gunung Palung National Park

New aerial footage released Wednesday showed smoke billowing from Indonesian forest fires as smog-choked Singapore's biggest supermarket chain announced a ban on products from a paper company accused over the haze shrouding Southeast Asia.

Fires illegally started to clear land for plantations on Indonesia's Sumatra island and the Indonesian part of Borneo have for weeks been producing thick haze that has cloaked Singapore and Malaysia, prompting the cancellation of outdoor events and school closures.

The smog-belching blazes are an annual occurrence during the dry season, but scientists have warned this year's could be the worst on record due to an El Nino weather system that has created tinder-dry conditions in Indonesia and increased the risk of fires.

The drone footage filmed by Greenpeace showed acrid haze rising from dense jungle, trees reduced to fire-blackened skeletons, vast swathes of burnt peatland, and a city shrouded in haze on the Indonesian part of Borneo.

"Companies destroying forests and draining peatland have made Indonesia's landscape into a huge carbon bomb, and the drought has given it a thousand fuses," said Bustar Maitar, Indonesian forest project leader for Greenpeace Southeast Asia.

"The Indonesian government can no longer turn a blind eye to this destruction when half of Asia is living with the consequences."

A rally in Jakarta on October 7, 2015 calls on the government to act to combat the haze caused by recent forest fires in Indonesia's Sumatra and Kalimantan

Pressure mounted in Singapore, where air quality has been unhealthy for weeks, with supermarket chain NTUC FairPrice, which belongs to a state-linked trades union, announcing the withdrawal from its shelves of all paper products sourced from Indonesian-owned Asia Pulp & Paper (APP), which has corporate offices in Singapore.

The company's suppliers are suspected of starting forest fires in Indonesia.

Meanwhile Singapore environmental and consumer groups asked home furnishings giant IKEA and retailers 7-Eleven and Watsons to certify that products they sell are not sourced from "companies accused of causing fires in Indonesia".

Mounting consumer pressure

Aida Greenbury, APP's Jakarta-based managing director for sustainability, told AFP that the company was working with the Indonesian military to fight forest fires in suppliers' landholdings, where more than 10,000 hectares (24,000 acres) had been affected.

"Regardless of who started the fires, we are working around the clock and bringing in additional resources to manage in our suppliers' land," she said in a statement.

A tourist (left) takes a "selfie" on a bridge overlooking the Singapore skyline choked with smog on September 29, 2015

"If any suppliers are found to have intentionally burned land, we will disengage with them. We are ready to step up and do more to address challenges in the landscape."

Tensions have been rising between the governments of Singapore and Indonesia over the haze, and the city-state's Ministry of Foreign Affairs asked Indonesia in a statement Wednesday for an "early response" to its requests for information on "errant companies suspected of being involved in the haze".

APP was asked by Singapore's National Environment Agency last month to supply information on its subsidiaries operating in Singapore and Indonesia, as well as measures taken by its suppliers to put out fires in their concessions.

The company said Wednesday it had provided information in response to the agency's request.

Under a 2014 law, Singapore can impose a fine of Sg$100,000 ($70,000) for each day that a local or foreign company contributes to unhealthy levels of haze pollution in Singapore, subject to a maximum total of Sg$2.0 million.