The Nortel patents auction saga took another twist Wednesday when Canadian Industry Minister Christian Paradis said that his government will hold an investigation into the sale to establish whether it complies with the terms of the Investment Canada Act.

On Monday, it was announced that a tech-industry consortium including Apple, Ericsson and Microsoft had successfully bid $4.5bn for Nortel’s patent assets, beating a highly-publicised Google campaign to the gavel. Under the terms of the Investment Canada Act, which covers foreign investment, the sale of any asset valued at more than C$312m must automatically be reviewed by the government to assess whether or not it’s of benefit to the country.

On the face of it, it would appear that the consortium has little to worry about: commentators in Canada have said that the patents were recorded as having next to no value on Nortel’s asset sheet, thanks in no small part to the difficulty companies have assessing the value of patents prior to their licensing or sale. It’s also unclear whether or not Nortel’s patent assets can be viewed as a “business” in its own right – a requirement of the law in question – as the company is reported to have made less than $10m a year on licensing and royalty payemtns.

What is giving rise to concern, however, is a growing sense that the sale will have a knock-on effect on competition. Prior to the auction, Google had been vocal about its motivation for bidding for the patents. The search giant claimed it needed to build up its patent portfolio to defend itself against legal attacks from rivals. With Android under increasing pressure from intellectual property claims, many commentators view the consortium’s bid for the patents not as a measure to protect themselves from each other so much as a massive arsenal with which to attack Google.

Under the circumstances, many observers found Mountain View’s approach to the auction a tad bewildering : the mathematically inclined among commentators pointed out that Google’s bids were based on obscure mathematical numbers such as the Brun’s and Meissel-Mertens constants and, once the bidding went past the $3bn mark, the company bid $3.14159bn – or Pi.

The Canadian government has only rejected foreign takeover bids on two previous occasions. Last year, BHP Billiton had a hostile takeover play for Potash Corp thrown out on the grounds of it offering no benefit to the country; in 2008, local aerospace technology firm McDonald Dettwiler was prevented from selling its space division to American defence firm Alliant Techsystems.