Shares in property portal Rightmove jumped as much as 25% after an Australian rival owned by Rupert Murdoch confirmed it is weighing up a bid for the UK firm.

REA Group told the City it “is considering a possible cash and share offer” for Rightmove, confirming earlier press reports.

The stock market statement saw Rightmove’s shares lift as high as 696p in early trading in London, valuing the business at around £5.5bn, up from £4.4bn on Friday night.

Shares in REA Group, held by News Corp, fell 5.5% on the Australian stock market.

Richmond-based REA Group, which employs almost 3,000 staff trades across Australia, Asia and the US under a series of brands, including PropTrack, realator.com and PropTiger.com.

The Australian firm says, “there are clear similarities between REA and Rightmove in terms of their leading market positions in the core residential business”.

It adds that an “enlarged group would represent a highly attractive investment opportunity for both REA and Rightmove shareholders”.

But the business points out: “REA has not approached, nor had any discussions with, Rightmove regarding any potential offer.”

Rightmove has been contacted regarding this story.