UK Foreign Office Minister Kim Howells has said the definition of what a war crime is may need to be reviewed after Israel's invasion of Lebanon.
Mr Howells says the notion of war crimes needs to be revised
He said the nature of the conflict meant a redefinition was needed, referring to actions by both sides.
Hezbollah's tactics in hiding weapons in civilian areas had gone to "new depths", he said.
He declined to call Israel's actions "disproportionate", but said they had been ineffective against Hezbollah.
Mr Howells, who visited the region in July to oversee the evacuation of UK nationals, was cross-questioned by MPs of the UK Parliament's influential Foreign Affairs Committee.
The minister alleged that Hezbollah had hidden caches of arms in schools and mosques, and rockets in apartment blocks in southern Lebanon.
"What I saw out there begs many questions about the way we try to define what constitutes a war crime in the future. I think we have to do a huge amount of reassessment in the future about how we define this kind of warfare," he said.
"Every time the Israelis responded... and smashed a building down, every picture of a burnt child and every picture of a building that had housed people [where] there was now pancake on the ground was propaganda for Hezbollah.
"And if an organisation like Hezbollah is ruthless enough to exploit those tactics, then one wonder how it can ever be possible in the future to, if you like, win the justice on your side against such an enemy."
Kim Howells has a reputation for plain speaking, says BBC correspondent Rob Broomby.
Mr Howells described the conflict as "horrific and terrible"
In front of the parliamentary committee, Mr Howells defended his government's handling of the Israeli invasion of Lebanon and its initial reluctance to call for a ceasefire.
He said they had wanted one that would last and he claimed they had now been "vindicated", although their position had generated hostility in Arab countries.
He called it a "horrific and terrible conflict", but he rejected suggestions the UK and US governments had stood back to allow the Israelis time to destroy Hezbollah.
On the question of the effectiveness of Israeli tactics against Hezbollah, he said:
"They assumed that an airborne assault would probably draw down upon them less international criticism than if they tried to reorganise that territory and that's obviously my assessment of what was going on.
"I thought it was the wrong tactics - not because of some notion of disproportionality, which I find a very difficult concept, but because I think it was not effective in reducing the ability of Hezbollah to survive.
"And in the end of course... Hezbollah emerged stronger for it."
During a trip to Lebanon during the 34-day conflict Mr Howells appeared to criticise Israel's military tactics, saying they were "very difficult, I think, to understand".
"The destruction of the infrastructure, the death of so many children and so many people... You know, if they're chasing Hezbollah, then go for Hezbollah. You don't go for the entire Lebanese nation," he said.