In a move to end a month-long stalemate, AMP Ltd, Australia's second-largest asset manager and French insurer Axa SA upped their bid for Axa Asia Pacific Holdings Ltd to A$12.9 billion. The wealth manager has a week to accept the sweetened offer.

In a statement, the Melbourne-based Axa Asia Pacific said its board would consider the proposal. The sweetened offer from AMP and France's biggest insurer raised the cash portion of the bid to A$6.22 a share, 53 per cent higher on the closing price before the original proposal a month ago.

According to analysts the revised offer is a very fair bid.

Axa SA, which owns 54 per cent of Axa Asia Pacific, plans to sell its stake to AMP. It will then buy back the units in eight Asian nations for A$9.1 billion.

According to AMP, the deal, Asia's biggest takeover offer this year, will double its financial advisers in Australia and New Zealand and increase its assets under management by 37 per cent to A$142 billion.

The offer from AMP and Axa SA, which the firms say is their best and final proposal, would lapse unless an agreement is reached before 21 December. The cash part of the bid has been raised by 54 cents to A41.92 a share even as the stock part remained unchanged.

Analysts say Axa Asia Pacific would find the proposal hard to reject.

Meanwhile, Axa Asia Pacific shares fell 1.7 per cent to A$5.72 in Sydney on Monday. The new offer value of A$6.22 a share is up from A$5.34 from what was first proposed.

However some companies with large shareholding in Axa Asia Pacific said they would not like to surrender the Asian business and would rather wait for the reaction of independent directors.

In addition to cash Axa Asia Pacific shareholders will receive 0.6896 AMP share for each stock held and will end up with 24 per cent of AMP if the deal is done.

The revised cash component of the bid which is A$515-million improvement has AMP contributing A$100 million and Axa SA contributing a further A$415 million, according to AMP. AMP added that the offer would still boost its earnings per share in the second year after the takeover.

The revised offer values Axa Asia Pacific's Australia and New Zealand businesses at 18.6 times estimated earnings, AMP said.

With operations in Hong Kong, China, Singapore, Indonesia, the Philippines, Thailand, India, Malaysia, Australia and New Zealand Axa Asia Pacific is responsible for the Axa group's Asia operations, according to its web site. It has a workforce of more than 2,300 in Australia and New Zealand and around 1,900 in Asia.