Essential post-Brexit freight software is unlikely to be ready on time for 1 January, those building it have warned.
A delay could hinder efforts to get products on to shop shelves and might push up prices.
The Association of Freight Software Suppliers (AFSS) said its members could not guarantee delivery because officials had failed to give it details and direction for the project.
But the government insisted the work was still "on track" for 1 January.
Her Majesty's Revenue and Customs (HMRC) is the department involved.
Source: The BBC