One of Australia's most deadly spiders is striking out as flood waters in south east NSW force them from their burrows

One of Australia's most feared spiders, flushed from its burrow by recent heavy rains, is striking out for higher ground, and more people in the south east are having close encounters with them.

Associate Professor Graham Nicholson from the University of Technology is an expert on the spider. He says it's not surprising that the funnel web spider is on the move right now.

"The spiders, especially the male of the species who go wandering the most, are looking for a mate around this time of year," he says.

"The rain actually gets them moving much more. They like it when it's moist and humid as they don't really like to dry out - it's detrimental for their health."

But you're least likely to run across a funnel web during the day. "They're mainly nocturnal animals, it's just too hot for them during the day," he says.

You're more likely to find them in your back yard where they tend to build burrows in rocky crevices, particularly in sandstone and anywhere there's some garden rubbish.

And the site of their burrows often show tell tale signs. "If it's built into a rocky environment you'll see a funnel shape approach to their burrow, with these long thick guy ropes coming out of the funnel.

"They use these to sense the movement of insects, and as the insects walk next to those guy ropes they generate a vibration into the burrow and the spider comes out and grabs them," says Professor Nicholson.

Spider Myths are just that

There have been a few myths about the funnel web spider that have been repeated over the years, including the one that they can jump and live on the bottom of a pool.

Funnel web spiders can't jump, in fact they prefer to keep the eight legs firmly on the ground. And while the spiders can swim, they can only survive in swimming pools for a few hours.

They're able to survive underwater because air is trapped by tiny hairs on their abdomen and they breathe though lungs located on the undersurface of the abdomen.

It's usually the chlorine that gets to them in the end.

The Sydney male funnel web is often regarded as the deadliest of the species but the spiders in the state's south east are closely related to them and just as lethal.

But Professor Nicholson warns that you should approach any funnel web, wherever you see them, with a lot of care. "I'd just avoid funnel webs where possible."

Which bite is worse ?

But how does the bite of the funnel web compare to redback spiders?

"If you get a decent bite from a funnel web - they're far more dangerous, and you're much more likely to die from a funnel web bite if sufficient venom has been injected.

"When people get bitten by red backs they'll get pretty sick, particularly young children and the elderly."

But Professor Nicholson says more people receive anti-venom for redback bites than they do for funnel webs because often when a funnel web bites they don't actually inject much venom.

The good news though, if you are bitten by a funnel web, you do have a couple of hours to do something about it. But Professor Nicholson doesn't advise dilly dallying around.

"You need to put a compression bandage over the bite site and down the limb. If the bite is on an arm or a leg then have it splintered off.

"Don't allow any movement in that limb, get the patient to rest, and then transfer the patient to a hospital as soon as you can," he advises.

So do the spiders have any redeeming features?

Professor Nicholson says that some of the venom has shown it can be toxic to insects but safe to human's and it may play a part in controlling pests in agriculture in the future.

In the meantime keep an eye out for any funnel web spider - they are on the move.