(Adds Nordic Capital, analysts, background, updates shares)

By Tarmo Virki

HELSINKI, May 16 (Reuters) - Finnish shareholders with a combined holding of about 10 percent in TietoEnator (TIE1V.HE: Quote, Profile, Research) said on Friday they would not accept a 1.08 billion euro ($1.67 billion) takeover offer from Sweden's Nordic Capital.

That would jeopardise a deal, analysts said, because private equity firm Nordic Capital, which has extended to May 23 its bid of 15 euros a share, has said its offer is conditional on 90 percent of shareholders accepting it.

"We made clear that we have well over 10 percent of shares," private investor Pekka Viljakainen, who owns 0.9 percent, told Reuters.

Shares in TietoEnator, a Nordic IT services company, were 1.1 percent lower at 16.05 euros by 0848 GMT, while the DJ Stoxx European technology share index was up more than 1 percent.

"Now Nordic Capital has to raise its offer or there would need to be other bidders. I see either option unlikely in the near term," said eQ Bank analyst Antti Saari.

Finnish mutual insurer Varma said it and three other institutional owners -- OP-Pohjola group, Society of Swedish Literature in Finland and the State Pension Fund -- holding a combined 8.7 percent, opposed the bid.

"The offer does not reflect TietoEnator's real value," Varma said in a statement.