After capturing this flood of communications in receiving dishes sheltered inside two 30m-high "radomes" shaped like giant golfballs, Waihopai automatically sends the bulk of them to analysts at the US National Security Agency in Maryland.
But the system's big drawback, says Green Party disarmament spokesman Keith Locke, is its reliance on certain keywords - only some of which are known to New Zealand security services - to alert its computers to particular messages.
Its "dictionary" computers were uncovered by Wellington researcher Nicky Hager in his 1996 book Secret Power, which was used by the European Parliament as the basis of a report which found that businesses and ordinary individuals were among Echelon's targets. Mr Hager was on a camping expedition yesterday, out of the Weekend Herald's (and presumably Echelon's) reach, but Mr Locke took up the baton of challenging the system's effectiveness against real threats.
He noted that billions of dollars-worth of electronic eavesdropping, to which New Zealand contributes more than $21 million a year through the Government Communications Security Bureau, had spectacularly failed to alert authorities to the terrorist attacks on the United States.
That was because any serious terrorist or criminal group would be careful to avoid phrases, such as "bin Laden", likely to be programmed into Echelon's computers.
Mr Locke said ordinary people using keywords in innocent conversations were much more likely to be listened in on, such as a woman reported by a Canadian ex-spy to have joined a list of suspected terrorists after telling a friend a play had "bombed'
Although bin Laden's al Qaeda network has been known to use e-mail and internet bulletin boards, messages can easily be encrypted to avoid electronic interception.
And seasoned Australian defence analyst Dr Des Ball says the world's most wanted man has avoided satellite phones since early 1999, after American missiles hit his suspected bases in retaliation for the bombing of US embassies in Africa.
But although the GCSB - Waihopai's operator - is New Zealand's largest intelligence agency, the more traditional Security Intelligence Service is adapting technology to a more hands-on approach to the war against terrorism.
Its novel offer of a freephone number - 0800-SIS-224 (or 0800-747-224) - to solicit information from the public against suspected terrorists in New Zealand has drawn at least 210 tips of "varied" interest.
The service is unsurprisingly vague about what it is gleaning, but director Richard Woods said in a rare briefing of reporters in April that it had already identified individuals in this country with links to terrorist groups overseas.
International terrorist groups "do have a long reach", Mr Woods said then, but he added that the SIS was unaware that any cells of such organisation had taken root in New Zealand.
Victoria University Centre for Strategic Studies director David Dickens warns that New Zealand should consider itself anything but immune from terrorist attacks, and go on a "war footing" with the US.
He believes this country could become the target of any of a number of threats, such as biological or chemical, or even the testing ground for terrorists to explode a suitcase-size nuclear bomb as a potent demonstration to the rest of the world.
Aircraft were not the only potential delivery vehicles for terrorists. A ship packed with explosives or even a road petrol tanker could be used to devastating effect.
New Zealand Refining Co asset manager Shaun Dyke said the oil industry had raised its level of alertness, but had not increased security measures markedly above normal.
"We are in liaison with the police and are being more vigilant in terms of our normal routines, but we live with this underlying threat every day all round the world."
Transpower, which operates the national electricity grid, and Auckland bulk water supplier Watercare also indicated that they were keeping watching briefs on existing security measures without taking action to beef these up at this stage.
President George W. Bush's decree freezing the assets of bin Laden and his terrorist associates filtered through to New Zealand almost immediately.
The Reserve Bank notified all banks about the presidential order and reminded them of their obligations.
Police experts said yesterday they had been busy all week dealing with an increased number of tips about money transfers by Middle Easterners.
But nothing suggested there was any substance to the reports at this stage.
Map: Opposing forces in the war against terror
Afghanistan facts and links
Full coverage: Terror in America
