Firefighters are being "pushed to their limits" with some working 17-hour shifts without a break to tackle moorland fires, claim union leaders.
Greater Manchester Fire and Rescue Service (GMFRS) crews have been tackling blazes near Saddleworth Moor, Tameside, since 24 June.
A whistleblower claimed bosses had made "basic errors" and provided "absolutely nothing", leaving them reliant on donations for supplies.
GMFRS said it was "doing its best".
The whistleblower, who has been tackling the blaze near Saddleworth Moor and who does not want to be named, claims his managers were guilty of "basic errors of judgement".
"The management is seriously lacking" with bosses "burying their heads in the sand", he said.
It follows reports firefighters are relying on donations of water and food while on the moor.
The whistleblower also claims some firefighters have been left on the moors for hours after their shifts because there is no transport to get them back to base.
He said on Sunday he was up for "a good five or six hours and I had a few litres of warm water and no food".
"All the front-line troops want is to be fed and watered and finish at a reasonable time" and bosses "can't even get that right", he said.
He added GMFRS asking for food and drink on Twitter made him feel "embarrassed".
Thanks to everybody who has donated refreshments. Please continue to direct all donations to Stalybridge Community Fire Station. If you would like to donate refreshments, we would appreciate isotonic drinks, cold food: i.e sandwiches 🍞,water ,fruit 🍏&energy or chocolate bars🍫— Manchester Fire (@manchesterfire) June 28, 2018
Assistant chief fire officer Tony Hunter said the incident near Saddleworth Moor and separate moorland fires on Winter Hill near Bolton which have been burning since Thursday were "unprecedented" and managers were doing all they could to support firefighters.
He said management recognised the hard work of the firefighters but the UK had not seen incidents like this for years with "challenging" conditions because of the size and quantity of the fires.
Gary Keary, chairman of the Fire Brigades Union in the North West, said crews were being pushed "to their limits" and claimed fire services were having to rely on donations for basic supplies such as sun cream and water.
He said: "Our firefighters have been working in difficult conditions to keep the fire from spreading and have done an amazing job," but added "it is deeply saddening that we have had to reach for the begging bowl".
The FBU said that since 2010, 700 firefighter posts have been cut in Greater Manchester and 314 axed in Lancashire.