Shoppers from the Republic spent €418 million in Northern Ireland in the year up to July, according to a new report from the Central Statistics Office (CSO).
This represents a slight fall from the €435 million recorded in the previous 12 months but the CSO says the difference is not statistically significant.
Some 14 per cent of households made at least one shopping trip to the North during the period, down from 16 per cent in the 2009 survey.
The proportion of Dublin households shopping across the Border fell from 21 per cent to 15 per cent.
However, the frequency of cross-Border shopping trips increased among those who do make the trip North. Households who shopped in the North made an average of 8.6 trips in the latest survey, compared to 6.7 in the 2009 survey.
Consumers in the Border counties are also hopping across the frontier more often; their frequency of cross-Border shopping trips increased from 5.9 per household to 8.6.
The average amount spent by households on shopping in the North on their most recent trip was €274, only slightly down on the previous year.
The nearer shoppers lived to the Border the more often they shopped in the North, the survey found, but the amount spent varied in inverse proportion to distance from the Border.
Less than 5 per cent of those living in the South-East, Mid-West and South-West made cross-Border shopping trips, the survey found.
Overall, those most likely to have shopped in Northern Ireland were those living in the Border area, two-income households, those aged between 30 and 44 and households with children. However, households with children and those where two people are working are shopping in the North less often, the survey shows.