New Delhi's Commonwealth Games are on the brink of a full-blown crisis after a pedestrian bridge collapsed outside the main stadium and amid complaints about filthy conditions in the athletes village.

Police say more than 20 labourers were injured, five seriously, after a 100-metre footbridge collapsed outside the Jawaharlal Nehru Stadium, which will host the opening ceremony in two weeks' time.

Meanwhile conditions in the athletes village have been described as "uninhabitable", with athlete representatives reporting that construction workers had left toilets in a "filthy" state and botched work on the apartments.

The Scottish and English teams have revealed they have been forced to don rubber gloves and clean toilets themselves in order to make their accommodation habitable.

And discus world champion Dani Samuels has delivered a huge blow to the Australian team, becoming the first Australian athlete to pull out of the Games because of security and health fears.

In a major embarrassment to organisers, the head of the English team, Craig Hunter, has revealed the scene at the athletes' village.

"It's just not satisfactory... the place is, you know, the toilets and what have you are clearly a mess," he said.

"But there are other significant issues as well. The air conditioning isn't working, there's flooding, doors have been hung in an incorrect manner, so a shower door that's supposed to open outwards, opens inwards so you can't actually physically get in.

"The hot and cold water feeds are reversed. There was a drain pipe from one of the adjacent towers with no downpipe and the water just gushed straight out of there and straight into our tower.

"We've got 10 people, 12 people on the ground now and we're donning rubber gloves and cleaning toilets, and that's not what we came out here to do.

"We came out here to set up a professional establishment for our team who are coming into compete in what is supposed to be one of the premiere sporting events in the world calendar."

Commonwealth Games Federation chief executive Mike Hooper also hit out at conditions in the village.

"We have emphasised the importance of addressing the issue of the condition and the cleanliness of the Games village, which I would have to say, in many many of the towers - I'm not going to pull any punches - are filthy and certainly uninhabitable," he said.

He also said there was "excrement in places it shouldn't be", referring to problems thought to be the result of labourers using the toilets in the residential complex.

But leading Indian sports official Lalit Bhanot has defended his country's preparations, saying foreigners have different standards of cleanliness and everything will be ready in time.

"The residential wing, yes [needs] some work, especially the deep cleaning needs to be done, but again I can only say it's a world class village, everything is fine," he said.

"Please try to understand, according to me and you the room is clean, fine. They want a certain standard of hygiene."

The chairman of the Scottish Commonwealth Games team, Michael Cavanagh, says things have now reached crisis point.

"The feedback like this has been given to the Organising Committee for at least the last two years and probably longer," he said.

"The Commonwealth Games Federation have had Mike Hooper as the CEO pretty much living in Delhi for the last two or three years to try and move things along and we keep getting told by the Indian organising committee that this is the way that they do things and they leave things late, but they will get there.

"But they are rapidly running out of time. They've left themselves too much to do and they're faced with a very, very difficult situation."

The mounting problems have claimed their first Australian casualty with the Australian discus thrower Dani Samuels pulling out.

The head of the Australian Commonwealth Games Association, Perry Crosswhite, says he expects Samuels will not be the last to drop out but he still believes the Games should go ahead.

"She got to a point where she kept thinking all the time about concerns about the security situation in Delhi and also about health issues and other things and to a point where she didn't think she could train anymore," he said.

"And she just didn't want to go through with it. I understand that.

"These [Games] are supposed to be fun and right now it's not all that fun. I tell you, when the first competition takes place and let's say an Indian athlete wins a gold medal, all the rest of it will go away."