"In tough times, the Pakistan Army is with you" MULTAN, Pakistan, Sept 5 (Reuters) - The message in black Urdu lettering on a white sack of supplies for flood relief says it all: "In tough times, the Pakistan Army is with you".

The powerful military has taken the lead in providing relief -- dwarfing the civilian government -- and in doing so has greatly enhanced its prestige and influence.

And while nobody expects it to take over, the renewed clout of the army is perhaps the biggest political change brought by the floods, one likely to define its relationship with, and leverage over, the civilian government for years to come.

"The military has in fact expanded its interests through the distribution of relief aid," said defence analyst Ayesha Siddiqa. "There is nothing today which does not fall within the military's purview."

The army, which became deeply unpopular in the final years of former president Pervez Musharraf, who seized power in a coup in 1999 and stepped down in 2008, had already clawed back considerable influence over foreign and security policy.

But in the flood relief it has become very visible as the only national institution with the manpower, the organisational skills and the equipment -- including helicopters and boats -- to help some 20 million affected by the floods.

At a boys' college turned warehouse in Multan, the main city in south Punjab, soldiers work around the clock to assemble packages of emergency relief. With leave cancelled and rations donated to the cause, the sense of pride is palpable.

The commander in charge of the area has been on the go since the floods hit a month before, says Major Farooq Feroze, the officer in charge of public relations in Multan.

"He is supervising each and every movement," he says. "He keeps us all alert. He himself is sleepless."

That is in stark contrast to the sluggish response of the civilian government, and the departure of President Asif Ali Zardari on a visit to France and Britain when the floods began.

Technically, the army is working on the orders of the government, and at the operational level, civilian and military authorities are working together closely.

"There is co-operation going on at every level," says Brigadier Zahid Usman at a field turned helicopter base in the town of Jampur in south Punjab. "We know where they are going; they know where we are going."

But the subtlety of that message is often lost in a country where much of the media is sympathetic to the army and where security officials grumble privately about the failings of democracy and the ruling Pakistan People's Party (PPP).