Britain's Rightmove said on Monday it would carefully consider Australian property listing firm REA Group's sweetened 6.1 billion pound ($8.12 billion) takeover bid for the company, after rejecting two previous proposals.

The latest proposal consists of 341 pence in cash and 0.0422 new REA shares, giving Rightmove an implied value of 770 pence per share.

Rightmove said the non-binding and 'highly conditional' bid would be considered by the board and the company's financial advisers. REA Group's first two proposals were quickly rejected by the target company.

Shares of Rightmove rose 2.8% to 693.6 pence by 0730 GMT. REA, which is 62% owned by Rupert Murdoch's News Corp, closed down 2.5% on Monday.

Rightmove chairperson Andrew Fisher said the company would respond to REA's third bid in due course.

The REA bid put forward on Monday is higher than the initial offer of 705 pence per share, or 5.6 billion pounds, and the second proposal of 749 pence per share. Rightmove had rejected both the proposals, saying they undervalued the company and were "uncertain, highly opportunistic and unattractive".

REA said before Rightmove's comment on its third bid that it had not had any "substantive engagement" with the takeover target, except for the rejections, and that it remained ready to engage immediately with the Rightmove board.

"We are genuinely disappointed at the lack of engagement by Rightmove's board and we strongly encourage the Rightmove board to engage," REA CEO Owen Wilson said in a statement.

Britain's housing market is triple the size of Australia's, according to analysts, and a deal would allow REA to expedite its international growth plans.

"The increased offer is clearly aimed at bringing the Rightmove board to the negotiating table," said S&P analyst Entcho Raykovski, noting News Corp's REA ownership would be reduced to about 49% if a deal progresses.

"...we note that REA has not declared the offer best and final, so there is scope for further increases."

REA has until Sept. 30 to make a formal offer for Rightmove or walk away.

The Australian company reiterated that it would look to apply for a secondary listing in London to give it access to a wider pool of investors.

($1 = 0.7510 pounds)

(Reporting by Scott Murdoch in Sydney, Himanshi Akhand and Aby Jose Koilparambil in Bengaluru, additional reporting by Iain Withers in London; Editing by Jamie Freed, Subhranshu Sahu and Muralikumar Anantharaman)