The manufacturing sector showed a "solid" improvement last month after it hit a four-month low in March, according to new figures.
The NCB Purchasing Managers' Index for April was 53.3 compared to 51.7 the previous month.
According to NCB, the index has now posted above the critical 50.0 no-change marker in each month since September 2003.
The improvement in the headline index was supported by accelerated rates of expansion of output and new orders, alongside a return to employment growth, the broker said.
NCB Stockbrokers chief economist Dermot O'Brien said: "The latest PMI shows that the dip in the pace of growth in manufacturing activity reported in March was a temporary one. Solid growth resumed in April, driven by a strengthening in new orders, especially from the domestic economy. Employment growth also recovered in April, albeit at a modest rate.
Growth of Irish manufacturers' new order volumes last month accelerated to a solid rate, improving on the 22-month low recorded in the previous month.
"A number of firms linked higher new orders to the introduction of new products, while there were also reports of an improvement in demand. However, growth of new business was largely centred on domestic customers as new work from abroad declined modestly," NCB said.