MONTREAL(Reuters) - Canada's corporate leaders are sounding the alarm over foreign acquisitions of the country's biggest companies, but looking for help from Ottawa to stem the tide may prove futile.This past week, Laurent Beaudoin, chief executive of plane and train maker Bombardier and Robert Brown, chief executive of aircraft simulator maker CAE, lamented the wave of foreign take-overs and buyouts of Canadian companies.

With major companies such as Alcan and BCE the target of foreign buyers, and with US hedge funds looking to cash in on the feeding frenzy, Canada is in danger of losing its corporate flagships, Beaudoin warned.

"We can't have in Canada only branches of foreign companies because at that point it would be to the detriment of the Canadian economy," Beaudoin said after Bombardier's annual meeting.

CAE's Brown, a former Ottawa mandarin who once held the helm at Bombardier, said Canada needs to be "in charge of its own destiny".

Ottawa cannot afford to have a hands-off attitude toward foreign take-overs, whether in the natural resources sector or others, he told reporters. Bombardier is family-controlled, while CAE is widely-held.

Beaudoin and Brown added their voices to a growing chorus of corporate chiefs worried that Canada is losing control of its best companies.

Concern has reached a crescendo since Alcoa's C$28.6 billion hostile take-over bid for venerable aluminium maker Alcan and interest by New York buyout firms Kohlberg, Kravis Roberts and Cerberus in backing take-private bids for BCE, Canada's biggest telecommunications group.

In recent weeks, the corporate choir has included Gordon Nixon, chief executive of Royal Bank of Canada and Dominic D'Alessandro, chief executive of Manulife Financial.

"We told them all to go to hell," Ted Rogers, chief executive of Rogers Communications, said of private equity specialists who came courting him as a partner to buy out telecom rival BCE.

"There is a panic mood that has set in," said Richard Janda, law professor and antitrust legal specialist at McGill University in Montreal.