* Says talks at preliminary stage
* Shares close up 12.8 percent at 632 pence
* Biggest shareholder says 750 pence per share a good price (Adds investor, updates share price)
By Victoria Bryan and Julie Crust
LONDON, July 13 (Reuters) - British oil and gas explorer Emerald Energy Plc said on Monday it received a takeover approach, continuing a wave of consolidation in the sector and lifting its shares to their highest in over a decade.
Syria and Colombia-focussed Emerald said talks regarding the possible cash offer are at an early stage and declined to comment on the price or the identity of the would-be purchaser.
The company's shares rose 10 percent on Friday on speculation of an offer at around 750 pence per share, which would value Emerald at about 470 million pounds ($757 million).
The stock closed up 12.8 percent at 632 pence, after earlier hitting 638.5 pence, the highest level since October 1998.
Waterford Finance & Investment, Emerald's largest shareholder, denied reports it was behind the takeover approach.
Waterford director Michael Kroupeev said he had not been presented with a 750 pence/share offer but that he would welcome it.
"It is a good number, I would be very interested to look at this offer," Kroupeev said.
The Financial Times reported that potential buyers included Canada's Gran Tierra Energy, which also has operations in Colombia and Peru.
Richard Savage, an analyst at Mirabaud Securities, said Emerald's main asset is its 50 percent stake in Block 26 in Syria and added that interest from parties connected to Gulfsands Petroleum, the operator of the block, cannot be ruled out.
Another analyst, who asked not to be named, ruled out U.S. buyers, saying they tend to avoid assets in Syria, but said Chinese, Indian or Canadian companies could be interested.
The oil and gas industry has seen a flurry of consolidation activity recently.
Heritage Oil agreed to a $6 billion merger with Turkey's Genel Energy, Chinese oil refiner Sinopec negotiated a $7.24 billion buy of Swiss oil explorer Addax Petroleum, and Venture Production at the weekend rejected a hostile $2 billion offer from Centrica. (Additional reporting by Tom Bergin) (Editing by David Cowell and Rupert Winchester)
($1=.6211 Pound)