Swiss watch exports enjoyed a strong start to the year as booming sales in the US and France offset a drop in sales in the world's biggest market of Hong Kong, according to data released on Tuesday.

Despite tougher comparisons from last year, overseas sales of Swiss watches rose 14.6% in real terms during January compared with the same period a year ago, according to data released by the Swiss customs office. In nominal terms, which adjusts for the impact of inflation, the gain was 16.9%.