* Affinity says will raise concerns with watchdog
* Says G8 was prepared to pay A$1.105 a share in June
* Offer valued Affinity at about A$0.70/share
* Stock in both firm down 3 pct amid wrangling (Recasts lead, adds details about offer, shares)
By Swati Pandey
SYDNEY, July 6 (Reuters) - Australian childcare operator Affinity Education on Monday urged shareholders not to accept a $121 million takeover offer from larger rival G8 Education Ltd, saying it would refer the all-share bid to regulators after what it called "opportunistic" off-market purchases of Affinity stock by G8.
Shares in both firms fell nearly 3 percent in early trading as investors reacted to the prospect of what began as a friendly approach for a full takeover by G8, Australia's largest listed childcare centre operator, turning into a protracted wrangle.
G8 Education on Friday offered one share in G8 for every 4.61 held in Affinity, valuing the latter at A$162 million ($121.40 million), or A$0.70 a share at Thursday's close. Meanwhile stock exchange filings showed G8 already bought nearly 20 percent of Affinity's shares in off-market deals last week.
In a letter to shareholders on Monday, Affinity disclosed for the first time it had been in takeover talks with G8 since April, with G8 - worth close to $900 million by market value - first offering to pay A$1.105 per share in an all-stock deal.
In June, G8 then lowered its offer to A$0.825 a share, a move Affinity said "undervalued" the company, before launching its July 3 bid at what was effectively a lower price still. At 0221 GMT, shares in Affinity were trading down 2.5 percent at A$0.6825, while G8 shares were down 3.8 percent and the index benchmark was down 1.3 percent.
In a statement on Monday issued after Affinity's letter to investors, G8 chair Jenny Hutson said, "the offer represents compelling value to Affinity Education shareholders."
In its letter, Affinity said it "was prepared to continue to engage in discussion with G8 but only if G8 revised the previous proposal." It said it has appointed advisers to help its board assess the G8 offer, and will raise concerns with the markets watchdog while advising investors not to take any action on G8's bid.
"It is important that shareholders are aware that G8 was very recently prepared to offer a higher value for Affinity shares which the Affinity board had considered was inadequate," Affinity said.
"This makes it clear that G8's share acquisitions and the current proposal are highly opportunistic." ($1 = 1.3344 Australian dollars) (Editing by Stephen Coates and Kenneth Maxwell)