The Singapore distributor behind the problematic cladding material, Alubond, said that it is conducting its own investigations even as it cooperates with the Singapore Civil Defence Force (SCDF).

In a statement last night, Chip Soon Aluminium appears to insist that the safety classifications of two models of composite panels, FRB1 and FRB2, were of the most stringent standard.

It wrote: "We have been shocked and dismayed to learn from the SCDF that they believe that FRB1 and FRB2 may not be of the requisite Class 0 standard as required under the Singapore Fire Code, as we have always believed these products to be fully compliant and properly certified.

"We understand from the manufacturer that these products have been used for building cladding in other countries."

SCDF, however, has said that model FRB1 is classified as the Class 0 for use as cladding on external walls, while FRB2 is classified as the less flame-retardant Class 1 for roofs and internal walls.

Stocks of both models were mixed together at Chip Soon's warehouse, added SCDF, and the panels from that pool were then supplied to 41 buildings for use as cladding on external walls.

Tests showed that the external walls of some of these buildings contain a mixture of both models, meaning that the cladding was not of the required Class 0 standard.

SCDF has lodged a police report and investigations are ongoing.

Chip Soon did not respond to Straits Times' queries for further elaboration.

In its statement, the homegrown firm said it is "demanding a response from the manufactuer of the products on the products' compliance with the appropriate standards".

The manufacturer is United Arab Emirates-based Eurocon Building Industries FZE.

Chip Soon, which deals in building materials here and abroad, was registered in 1982 with a paid-up capital of $4.3 million. Company records show that the firm is run by two directors - Mr Moh Chiew Cheng and Mr Phua Kay Lock.