In a statement, GSIS executive vice-president for finance Omelita Tiangco, said the deadline has been moved to a later date to give way to requests of interested parties and to get the best possible offer.
GSIS is selling its 12.4 percent shareholdings in Equitable PCIBank, the countrys third largest bank.
Tiangco said the GSIS recently received inquiries from two foreign investor groups based in California. These new parties, according to Tiangco, have sought an extension to allow them to raise funds for the highly-anticipated bidding.
Earlier, GSIS received offers from two foreign investors for the purchase of the funds shareholdings at P92 each share.
In the same notice, the GSIS said it would only accept a minimum cash offer of P92 per share for its 90,078,333 Equitable PCI shares, worth about P8.29 billion. This is equivalent to the amount the GSIS invested in 1999 to purchase its stake in the bank.
GSIS also reiterated that it will only accept cash offers.
Apart from this condition, all bids must be accompanied by cashiers or managers check equivalent to 10 percent of the offer price.
The April 6 opening of bids will take place at the GSIS main office in Pasay City.
The state-run pension funds announcement of the block sale came in the midst of the standing offer of the SM Group of retail tycoon Henry Sy to merge its banking arm Banco de Oro with Equitable-PCI through a share swap.
The Sy group proposed to offer 1.6 shares of Banco de Oro for every share of Equitable PCI. Analysts said the offer is equivalent to about P76 per share, discounting goodwill and the banks bad assets.
However, GSIS president and general manager Winston Garcia has branded the merger offer as "grossly and scandalously disadvantageous" to the GSIS and its shareholders.