Shopper numbers in the North were 6% lower last month than a year ago, it was revealed.
These figures are considerably worse than the whole UK where the total was up 0.1%, retailers said.
Northern Ireland Retail Consortium director Aodhan Connolly said: "June has been a disappointing month on Northern Ireland's high streets.
"Despite the good offers and promotions that are available at the moment, shoppers have continued to stay away.
"Our figures show that footfall fell again this month, as it has done for four months in a row. This is despite overall shopper numbers increasing in the UK as a whole.
"Northern Ireland retains the unfortunate position of showing the worst performance in the UK.
"As the weather improves, retailers will be hoping that the summer sunshine helps to tempt customers back to the high street in the coming months."
In June, shopper numbers in the North were 5.9% lower than a year ago, compared with a 3.1% decline in May 2013, the consortium said.