A statement from the British bank said: "Barclays is considering possible alternative offer structures, including introduction of a partial cash consideration element into the offer."
The bank's statement comes after the rival consortium which is also vying for ABN Amro this week announced that it has sweetened its $97 billion bid by upping the proportion of the cash component from 79 per cent to 93 per cent.
Barclays' current offer, meanwhile, which was initially accepted by ABN Amro in April, stands at $86 billion.
However, Barclays chairman John Varley said that any amendments to the bid "will be subject to the satisfaction of the pre-conditions referred to in the original press release dated 23 April, 2007".
He added: "If any changes to Barclays' offer were made they would be consistent with its prior public statements regarding the strict financial criteria it applies to merger and acquisition transactions and ensuring that the terms of any transaction are in the interests of its existing shareholders."
The rival consortium is led by Royal Bank of Scotland and includes Spanish bank Santander and Fortis Group.