The decision by the Australian Competition and Consumer Commission to review the takeover occurred as the share price of one of the players in the changes, Gunns Ltd, plummeted to a record low.

Gunns chief executive Greg L'Estrange last night was at a loss to explain the plunge.

Woolworths subsidiary John Danks and Son has agreed to pay $40million for Gunns' chain of Mitre 10 stores and is finalising a deal to acquire Launceston-based Becks Timber and Hardware.

The agreements mean Tasmanians wanting to buy groceries, petrol, liquor and now hardware face a market increasingly dominated by the two major retailers.

Both Woolworths and Coles have also expressed their desire to include pharmacy in their supermarket operations.

Tasmanian Chamber of Commerce and Industry chief executive Robert Wallace played down concern that the apparent duopoly was limiting choice in Tasmania.

"There has been movement away from family-owned businesses over the last couple of decades," he said.

Mr Wallace said Woolworths' eagerness to buy into the state's hardware industry indicated that, despite its size, Tasmania was an attractive investment option for other national and international players.

It also makes the North a key battleground between Woolworths and Wesfarmers, which owns the successful Bunnings chain as well as rival supermarket chain Coles.

Woolworths entered Australia's $24billion hardware industry last year, when it acquired Danks in a joint venture with US hardware giant Lowe's Companies - the world's second-biggest home improvement retailer.

The ACCC cleared the Danks takeover after securing court- enforceable undertakings from the joint venture parties to address concerns over discrimination against wholesale customers.