By Ritsuko Ando

NEW YORK - Cisco Systems Inc's $3 billion takeover bid for Norwegian company Tandberg ASA is facing increased opposition, with investors owning as much as 30 percent of the video conferencing company's shares now demanding more money.

Investment adviser OppenheimerFunds, on behalf of funds and accounts owning a 5.78 percent stake in Tandberg, said on Wednesday that it will not agree to sell their 6.48 million shares to Cisco at the current offer price of 153.50 crowns per share.

OppenheimerFunds said it remains open to better offers from Cisco or other strategic partners.

Another investor group, represented by brokerage SEB Enskilda and holding 24 percent of Tandberg shares, snubbed Cisco's bid last month.

OppenheimerFunds spokesman Bruce Dunbar said it was not part of the earlier group.

The deal has been endorsed by Tandberg's board of directors but it needs to be approved by 90 percent of shareholders.

Cisco on Wednesday reiterated its view that the company is offering a fair price for Tandberg.

"Further, Cisco's general approach to M&A activities is that no acquisition should be pursued or completed if it runs counter to the broader principles of prudence and financial fairness," it said in a statement.

A person familiar with the matter had told Reuters last week that Cisco is mulling its options including withdrawing or raising the bid. Tandberg shareholders have until November 9 to accept the tender offer.

Cisco is set to announce its quarterly results on Wednesday, and analysts are listening for Chief Executive John Chambers' comments on the Tandberg deal.

Some analysts have said they expect Cisco to sweeten the offer, while others have said it could play hardball and threaten to drop its bid -- which will likely lead to a drop in Tandberg shares since no other suitor has emerged publicly.

Shares of Cisco closed up 1.7 percent at $23.30. Tandberg shares closed down 0.13 percent at 150.20 euros.

[via Reuters]