Within hours of Cyclone Nargis crossing the Burmese coastline seven weeks ago governments pledged aid and agencies launched international appeals. The response was immediate, but the Red Cross says that 2.4 million people remain in urgent need of help.

Given this need, most people will be keen to give as tax-efficiently as possible. Yet figures from the Red Cross and the Disasters Emergency Committee (DEC), the UK umbrella organisation for aid agencies, indicate that hundreds of thousands of pounds are lost to appeals because donors fail to tick the Gift Aid box.

Under the Gift Aid scheme, charities can claim an extra 28p from the Revenue for every pound donated by a taxpayer. The DEC, which is running a co-ordinated Burma campaign for 12 member charities - including Oxfam and Save the Children - has raised £15 million. But Patricia Sanders, of the DEC, says that one in five donors has not pledged using Gift Aid. “Many do not understand that they are not paying the extra themselves,” she says.

The British Red Cross's Myanmar (Burma) Cyclone Appeal, meanwhile, has raised £1.2 million. The charity says that donors' failure to use Gift Aid has cost the fund £51,000 to date.

Jack Durrell, of the British Red Cross, says that money given in collections - in the street, for example - cannot be donated through Gift Aid, but he urges those who give online or by phone to maximise their gift. “With Gift Aid we can reach even more people in need,” he says.

However, Gidon Freeman, of the DEC, is concerned that some people have not given at all, in the mistaken belief that aid is siphoned off by Burma's junta.

France Hurtubise, of the International Federation of Red Cross and Red Crescent Societies, says that poor communications hampered aid provision in the cyclone's immediate aftermath, but the situation has improved with the acquisition of boats to ferry supplies. She adds that one million litres of clean water a day are now reaching at least 600,000 people in the stricken delta region. Last week about 82,000 people received Red Cross or Red Crescent shelter materials and aid kits, but aid has yet to reach the most remote villages.

Readers can donate to the DEC's Burma appeal online at dec.org.uk, at banks, post offices, and by telephone on 0870 6060900; or donate up to £1.50 by texting “DONATE” to 83696. Donations are allocated to member charities in proportion to their contribution to the campaign's running costs. “That isn't rigid. If a smaller charity has a disproportionate effect on the ground, we give it more,” Mr Freeman says, adding that this makes gifts to the DEC more effective than those to individual charities.

Case Study, Putting the fun into fundraising

Mary Kavanagh, 59, has been responding to charity appeals for decades. But rather than give cash, the retired nurse prefers to help with fundraising and has organised a number of events at Camden School for Girls, which her daughter attended until 2006.

Together with the school's head teacher, Anne Canning, she is organising a “Midsummer Fantasia” evening, at which she hopes to raise several thousand pounds for the Red Cross's Burma appeal.

Mrs Kavanagh, pictured, left, with Ms Canning, says: “I did something similar for the tsunami of December 2004. We had entertainment from the students, a barbecue and stalls selling cakes, plus a tombola with fantastic prizes donated by parents and local businesses. People who can't afford to give hard cash to appeals can get involved by organising, or contributing to, events like this - baking cakes, for example. I meet super people and get huge enjoyment from it.”