Asos boss Nick Robertson admitted that Australia was “not a great place to be” as the weak Australian dollar stunted its growth in the country.

Robertson said that the fashion etail giant’s products appeared 13% more expensive to the Australian consumer because of the exchange rate.

Australia had been one of Asos’ biggest growth markets. Its rest of the world sales, which is dominated by Australia, soared 35% in its full year to August 31, 2013. However, in the four months to December 31 growth slowed to 19%.

Robertson said he planned to make smart, tactical promotions in Australia to help stimulate growth.

The retailer’s sales momentum in the US also slowed, impacted by a lack of zonal pricing with UK prices less competitive than the local market. However, Asos will launch zonal pricing in the US to help accelerate performance in the second half.

Despite the growth slowdown in some of its overseas markets, Asos achieved a 38% jump in total retail sales to £335.7m in the four months to December 31.

UK sales soared 37% and international sales, which make up 60% of the retail total, rose 38%.

Robertson said that its UK sales jump was driven by its investment in improving its delivery service by offering speedier service, text alerts and later next day delivery cut-offs.

Robertson said that the UK market was promotional over the Christmas period and although it “optically played the promotional game” it had tighter control of stock that helped margins increase 90 basis points.

Asos is set to break through the £1bn sales barrier this year, according to analyst Peel Hunt, ahead of the retailer’s 2015 target.

Asos sales surge as Christmas shoppers flock online