According to (unfortunately undated) official details, the symbolism of the flag reads as follows:
"The new ASEAN flag represents a stable, peaceful, united and dynamic ASEAN. The colours of the flag - blue, red, white and yellow - represent the main colours of the flags of all the ASEAN countries. The blue represents peace and stability. Red depicts courage and dynamism. White shows purity and yellow symbolizes prosperity. The tens stalks of padi represent the dream of ASEAN'S Founding Fathers for an ASEAN comprising all the ten countries in Southeast Asia bound together in friendship and solidarity. The circle represents the unity of ASEAN."
According to Pavillons nationaux et marques distinctives, the flag has proportion 2:3, the diameter of the disc is ca. 1/2th of the flag length, and the blue shade is dark.
Official colour specifications (for paper printing) are:
Blue: Pantone 286c - C100/M60/Y0/K5
Red: Pantone 032c - C0/M90/Y90/K0
Yellow: Pantone Process yellow - C0/M0/Y100/K0
According to (unfortunately undated) official details, for textiles, the colours should be:
Blue: Pantone 19-4053 TC
Red: Pantone 18-1655 TC
White: Pantone 11-4202 TC
Yellow: 13-0758 TC.
The ratio is given as 2:3, and "the size specifications for official flags" are: Table Flag 10 cm x 15 cm, Room Flag 100 cm x 150 cm, Car Flag 10 cm x 30 cm and
Field Flag 200 cm x 300 cm.
The white disk is 0.6 of the hoist, and the height of the yellow emblem is a half of that distance. The width of the white fimbriation is, according to Chris Southwort, 1/80 of the hoist.
ASEAN is the Association of South East Asian Nations and was formed on 8 August 1967, with 5 members, Indonesia, Malaysia, Philippines, Singapore, Thailand. Brunei became the 6th in 1984 and Vietnam the 7th member in 1995. On May 31, 1997 at the ASEAN foreign minsters meeting, it was decided to admit Cambodia, Laos and Myanmar in a few months' time. To represent the 10 nations, a new flag was unveiled which had in the center a stylized device featuring 10 rice stalks. I haven't seen the flag in color but the background is AFAIK light blue. ASEAN has its seat in Jakarta, Indonesia.
The old logo had 6 rice stalks.
A Reuters news report announced that ASEAN will keep the flag with 10 rice stalks despite not taking in Cambodia due to its internal war. ASEAN Secretary-General Ajit Singh stated "It will still be the 10 stalks of paddy, and the reason we have maintained it is because this is the vision of all the ASEAN 10."
The flag is described as "The new flag unveiled late in May comprises a blue background with a centered red circle enclosing 10 yellow stalks of rice paddy. A thin white ring encircles the red ring." Reuters quoted ASEAN's explanation of the symbolism: ``The 10 stalks of paddy represent the dream of ASEAN's founding fathers for an ASEAN comprising all the 10 countries in southeast Asia bound together in friendship and solidarity.''