LONDON (Reuters) - Shares in British engineering software firm Flomerics Group (FLO.L) surged on Friday after rejecting a buyout offer from larger U.S. rival Mentor Graphics, saying it would explore interest from several other parties.

Flomerics is up 15 percent to 102 pence a share at 0810 GMT, approaching Mentor's (MENT.O) offer price of 104 pence in cash for all the stock in Flomerics.

Discussions with other interested parties are at an early stage, with no certainty that an alternative offer would be made, Flomerics chairman David Mann said in a statement.

Flomerics, which supplies simulation software to the engineering and electronics industries, announced in April record full-year turnover of 16.3 million pounds ($31.84 million). Adjusted pretax losses amounted to 1.3 million pounds.

Flomerics supplies blue-chip customers including IBM (IBM.N), Siemens (SIEGn.DE) and Nokia (NOK1V.HE).

Mentor had a 26.3 percent stake in Flomerics in March, while a fifth is held by company management and staff. Japan's Kozo Keikaku Engineering (4748.Q) owns a 5 percent stake.

(Reporting by Hsu Chuang Khoo, editing by Will Waterman)