Northern Ireland companies reported strong growth in their order books, which boosted confidence last month, according to a survey by Ulster Bank.
Every month the bank asks firms across the private sector about issues such as staffing levels, exports and new orders.
It is considered a reliable indicator of economic performance.
It suggests the private sector started 2024 in a stronger position than that on which it ended 2023.
The bank’s chief economist, Richard Ramsey, said optimism was at a 32-month high.
“The biggest surprise in the latest survey was the surge in business confidence,” he said.
“Local firms were their most optimistic about future output levels since May 2021. The positive sentiment was evident across all four sectors.”
Mr Ramsey said the renewed optimism was linked to the launch of new products and higher orders.
“Significantly, the notable improvement in the outlook predates the restoration of Stormont,” he said.
“The impact on sentiment of the political developments should become apparent in February’s survey.”
Three of the four sectors – manufacturing, services and retail – all reported an increase in business activity in January, with only the construction sector reporting a fall.
Mr Ramsey said a notable pick-up in domestic demand led to the first rise in new orders in eight months.
“A surge in retail demand and a return to growth in manufacturing orders more than offset the continued declines in services and construction,” he said.
Manufacturing, services and constructions firms all took on more staff last month, with only retailers reducing their staffing levels for the first time in more than a year.