The Olympic stadium is still under construction
Steps have been taken to prevent the London Olympic site being hit by sewage travelling at "40 miles an hour", a Home Office minister has said.
Lord West was briefing peers on what is being done to protect critical infrastructure on the 2012 site.
He also revealed the games' computer system, which controls ticketing, had already come under cyber attack.
He told a House of Lords sub-committee government and industrial computers in the UK were under "constant" attack.
The cyber-security minister said: "Almost every single government and industrial and other site is under attack, probably quite regularly. There are always people trying to get into these things.
"And so on the Olympic system, for example, we have found there have been some attacks on that and we are aware of those and we are dealing with them, but it's something that we have to constantly monitor."
He said he was confident the UK's national water and electricity grids were adequately protected from cyber attack, although work was under way to protect the water supply from being poisoned.
He said the telecommunications network was more vulnerable to attack as, by definition, it was connected to the internet.
But he said UK telecoms systems were harder to break into than those in the US "because they went into the computer world so much before us".
He was quizzed about what had been done to protect the 2012 Olympics site in Stratford, East London.
"There has been a lot physical work to ensure, for example, overhead power lines and everything now go underground," he told the Lords EU sub-committee.
"Things like the sewage system - that has been adjusted and we have protection in place for that because all of North London's sewage suddenly shooting on to the Olympics site - it travels at about 40 miles an hour down three pipes, each of which is a 12 inch bore, would be quite exciting I think, and those aspects are being looked at as well."
Lord West was also asked about Britain's response to the news that internet giant Google may pull out of China following a "sophisticated and targeted" cyber attack.
Asked if the UK government had "mechanisms in place to debrief Google people as to the type of penetration that has taken place", he replied: "Yes."
Lord West has spoken in the past about the UK being under cyber attack from other countries including China and Russia.
The peer is in charge of a unit, based at the government's secret listening post GCHQ, aimed at gathering intelligence about cyber threats from other countries and protecting UK infrastructure.
He said it was often "very difficult" to find out where cyber attacks were coming from and that meant there were ethical and legal questions about whether it was possible to strike back.
But he said there was no doubt that other countries were mounting such attacks on UK government and industrial systems.
"We know that state actors have got into major industrial concerns and taken every bit of data, let's say about an aeroplane engine," he told the committee, and there were examples of countries "doing other things - trying to get into other countries' systems".
He told the committee the threat from cyber attacks was "very serious".
"We are toe-to-toe with these people today... it is a constant struggle. These people constantly - and it ranges from state actors, through organised criminals, individual criminals, through hackers - who might only do it because they think it is fun but, my God, they can do unbelievable damage."
He said terrorists "have not really done this on a great scale but of course you can learn very quickly".
The committee, which has been taking evidence from industry experts and legislators for the past few months, is due to produce its report on protecting the UK's national infrastructure from cyber attack in March.