New Zealand dairy giant Fonterra has said it is extending the closing date of its offer to acquire Australian dairy firm National Foods to 15 February.

Fonterra's A$1.6bn (US$1.23bn) bid was previously due to expire on 1 February. However, its bid of $5.45 per share has been exceeded by a $6.00 per share bid from San Miguel, the Philippines-based food and beverage company.

Fonterra has also asked National Foods for more detailed financial information so it can decide whether or not to make a higher offer, reported Dow Jones News, citing industry sources.