David Davis and Greg Clark are visiting Northern Ireland as part of their work on future customs arrangements with the EU after Brexit.
The Brexit and Business secretaries joined their Northern Ireland counterpart Karen Bradley in meeting cross-border companies as part of their working group focusing on a proposed "highly-streamlined" option for tackling one of the thorniest outstanding issues.
The Irish border and the potential impact of regulatory differences is central to negotiations on a pact ahead of next year's withdrawal from the EU.
The Prime Minister has split her ministers into two teams as they work towards a reconciliation on how to manage arrangements with the EU after the exit.
One group - Brexiteers Liam Fox, Michael Gove and Remain-backing Cabinet Office minister David Lidington are considering a "customs partnership" whereby the UK would collect tariffs on behalf of the EU without the need for new border checks.
The Brexit Secretary's group will look at "maximum facilitation" - a solution based on using technology to minimise the need for customs checks after Brexit.
The maximum facilitation group is in Northern Ireland to meet representatives from the freight industry, cross-border businesses and community stakeholders to further explore how the customs model could address the unique circumstances of Northern Ireland, a statement from the Brexit Department said.
It added: "Both of the customs models currently under consideration are designed to meet the UK's three guiding principles: allowing us to trade goods and services as freely as possible with the EU, enable us to have an independent trade policy, and avoiding any hard border between Northern Ireland and Ireland while maintaining the constitutional and economic integrity of the United Kingdom."
The ministers are not expected to talk to members of the media during their visit.