OSLO (Reuters) - Marine Harvest (>> Marine Harvest ASA), the world's biggest fish farmer, may raise its $1.7 billion bid for rival Cermaq (>> Cermaq ASA) if the target company's shareholders drop plans to take over Peruvian fish feed maker Copeinca (>> Copeinca ASA), it said on Tuesday.

Marine Harvest has tentatively offered 105 crowns in cash and shares for each Cermaq share and has said it would only go ahead with a formal bid if Cermaq drops the Copeinca deal.

"We could be prepared to improve both the price and composition of our offer in order to find an amicable solution acceptable to all parties," Marine Harvest said.

Shareholders in state-controlled Cermaq will vote on Tuesday whether to approve buying Copeinca, and the Norwegian government, which has a 43.5-percent stake in the firm, has said it will vote in favour of the proposal.

The deal will, however, need the support of owners representing two-thirds of the votes present at the general assembly to go through, and the next largest owners - Lansdowne and Marine Harvest itself - with 8.6 and 5.4 percent respectively - have said they will vote against the acquisition.

Marine Harvest, controlled by shipping tycoon John Fredriksen, has argued that Cermaq lacks management resources to cope with Copeinca, and has no experience of dealing with political risk in Peru, while Cermaq sees Copeinca's anchovy fish oil as an important strategic asset.ž

Separately, China Fishery Group (>> China Fishery Group Limited), which had also bid for Copeinca, said it would be willing to raise its own bid for the Peruvian firm, if Cermaq's shareholders rejected the deal on Tuesday.

(Reporting by Victoria Klesty and Balazs Koeanyi; Editing by Mark Potter)