Intervening in Pfizer's proposed acquisition of AstraZeneca using public interest rules is "quite tricky" and could be a lengthy process, British business minister Vince Cable said on Tuesday.

"The framework which we have under the act, as you know, confines the public interest test quite narrowly and, of course, all of that takes place within the framework of European merger law," he told British lawmakers on Tuesday.

The U.S. drugmaker has stirred up a political storm with its $106 billion plan to acquire AstraZeneca, which has been rebuffed by the smaller British company.

The deal would be the largest foreign takeover of a British firm and is opposed by many scientists, trade unions and politicians who fear for British science jobs given Pfizer's track record of cost cutting after past acquisitions.

(Reporting by Ben Hirschler; editing by Kate Holton)