US retail sales are expected to increase 4.1% this holiday season but will be tempered by political and fiscal uncertainties, according to the National Retail Federation (NRF).

Holiday sales are set to rise to US$586.1bn this year compared to an actual sales growth of 5.6% last year. The forecast is higher than the ten-year average of 3.5% growth, the NRF said. 

However, unimpressive job and income growth as well as an unemployment rate of 8%, could weigh on sales this year. 

"This is the most optimistic forecast NRF has released since the recession. In spite of the uncertainties that exist in our economy and among consumers, we believe we'll see solid holiday sales growth this year," said NRF president and CEO Matthew Shay.

"Variables including an upcoming presidential election, confusion surrounding the 'fiscal cliff' and concern relating to future economic growth could all combine to affect consumers' spending plans, but overall we are optimistic that retailers promotions will hit the right chord with holiday shoppers."