Farmers in England who have not received their Basic Payment Scheme payment by the end of April will receive 50 per cent bridging payments.
The Rural Payments Agency’s chief executive has announced the money will initially be paid from Treasury funds and then topped up at a later date.
Mr Grimshaw said he was fully aware of the "frustration and anxiety" felt by farmers still waiting for their money and acknowledged that the RPA "could have done more".
"It's been an incredibly challenging year," he said. "Our experiences from 2015 will give us valuable insights into 2016."
"We will pay these claims as soon as we can but these are complex claims that are proving harder to complete than anticipated," stressed Mr Grimshaw.
The Tenants Farmers Association (TFA) welcomed the bridging of payments but said it would continue to push for an extension to the current deadline of May 16.
TFA chief executive George Dunn said the organisation has been working closely with the RPA to fulfil payments, but following a meeting of the RPA's Technical Stakeholder Group on April 13 there were a "significant number" of issues that still need to be resolved.
"Although some progress was made, there are a significant number of issues which remain outstanding.
"With a month to deadline the TFA viewed the meeting as an important line in the sand."
"Without such an extension both the RPA and BPS applicants will be placed under intolerable stress," concluded Mr Dunn.
Delays in payments to farmers are putting incredible financial pressure on cash flows, at a time when farmgate prices are down across the board and markets are particularly volatile.
Farmers in desperate situation
CLA President Ross Murray said: "Many of the farmers that have still not been paid for work they carried out as long ago as autumn 2014, are in a desperate situation.
"Given how late this has become, if they can’t be paid in full it is right they receive a bridging payment.
"We are disappointed that yet again emergency measures have become necessary. In due course there will need to be yet another review into how this situation has come to arise.
"We advised the RPA leadership to consider a part payment process for complex claims in the autumn of 2015 and it is important to understand why any action was not taken sooner.
"In the meantime we remain absolutely focused on working with the RPA leadership and the Secretary of State to ensure they are finding solutions to these mounting problems."
