Companies are losing time and business due to a lack of communication between the Welsh and UK governments, a business group says.
The Federation of Small Businesses (FSB) in Wales said the problem must be resolved "as a matter of urgency" due to the problems caused by coronavirus.
The Welsh Government said it was working with Westminster to provide assurances.
The UK Government said they had worked closely and constructively together.
A £1.4bn package of support for businesses was announced by the Welsh Government after the UK Government laid out its financial measures to shore up the economy.
These included £330bn in loans and £20bn in other aid.
Ben Francis, FSB Wales policy chair, said that the unanimity of purpose seen between the two governments on health "hasn't always been the approach to protecting businesses".
He said: "At this time of national crisis, it is the reasonable expectation of business that UK and Welsh governments will not just work together, but also that they'll demonstrate this to those that rely on them.
"Over the last few weeks, we have heard from each government about gaps in intelligence provided and decisions not being communicated by the other.
"At a time when the priority is for businesses to be reassured by governments, this must be resolved as a matter of urgency.
"We have seen a very welcome unanimity of purpose, clarity and resolve on health messaging on coronavirus from UK and Welsh governments.
"That is of course entirely right to effectively protect health. However, this hasn't always been the approach to protecting businesses. Business is in crisis and this must be resolved."
A UK Government spokesman said it was the "biggest challenge" Westminster and Cardiff Bay had faced together.
"Unprecedented action has been taken by the UK Government at extraordinary speed because we know that businesses, communities and individuals all need help urgently.
"Throughout the crisis, we have worked closely and constructively with the Welsh Government and the other devolved administrations to keep the whole of the UK safe."
They said Welsh Government officials and ministers had been involved in Cobra meetings and committees since the pandemic began and would continue to be a "key part" of the planning and communication.
A Welsh Government spokesperson said: "This is an unprecedented period and we are doing everything we can to support businesses through this incredibly difficult time including developing our package of support.
"We continue to work with the UK Government in order to provide the assurance business needs to see them through the coronavirus pandemic."