By The Canadian Press

TORONTO - Hudbay Minerals Inc. (TSX:HBM.TO - News) has extended its hostile takeover offer for Augusta Resource Corp. (TSX:AZC.TO - News) until May 27.

The offer had been set to expire Friday.

Augusta is developing the Rosemont copper-molybdenum project near Tucson, Ariz.

The extension by Hudbay follows a decision by the B.C. Securities Commission to allow Augusta's shareholder rights plan to remain in place unless Hudbay extends its offer to July 16.

If Hudbay extends its offer to July 16, the rights plan will be blocked on July 15.

Hudbay, which owns about a 16 per cent stake in Augusta, has offered 0.315 of a Hudbay share for each Augusta share, valuing the company at about $458 million or $3.15 per share based on share prices Friday.

Shares in Augusta closed down 13 cents at $3.01 on the Toronto Stock Exchange on Friday, while Hudbay shares closed up 35 cents at $10.

Augusta adopted a shareholder rights plan last year following Hudbay's acquisition of a large stake in the company. Its shareholders reaffirmed the plan at the company's annual meeting earlier this month.