National Australian Bank has agreed to put on hold its exclusive $12 billion acquisition of AXA Asia Pacific for another three weeks.

According to media reports, the source familiar with the situation said the exclusive takeover was due to expire at midnight last night, but both groups agreed later on for an extension to another two to four weeks to give time for NAB to persuade the competition regulator to agree to the second largest Australian financial services deal.

Papers also said the bank were in talks with smaller wealth manager IOOF Holdings and life insurer Tower Australia to sell AXA AP's Pacific North investments, which is believed to be the key reason why the Australia Competition and Consumer Commission rejected the contract.

ACCC last month stopped the deal due to lack of competition in the retail investment platforms. The competition regulator has yet to reveal its detailed reasons for not giving NAB the go ahead signal.

Retail investment platform is a software that ties the customer and financial products with the wealth manager.

A spokesperson for NAB declined to comment while AXA AP's representative could not be reached for comments.

It is believed that the takeover extension may allow NAB to refine its revised contract. The deal may prompt investors to take the $6.43 cash on offer that should the capital raising of NAB if the competition regulator approves the deal.

Meanwhile, rival bidder AMP continues to express its interest for a bid with APH.

Shares in NAB closed at A$24.63, and AXA at A$5.82 on Monday.