The group said turnover at its hire arm - which rents out morning suits for weddings and other special occasions - was 3.8% down in the 16 weeks to May 17. The firm's hire unit accounts for 16% of group revenues.
But its retail division, selling business suits and more casual menswear did better, with like-for-like sales up 8.5%, helping the the overall business to improve by 6.3%.
Moss Bros has staged a recovery in recent years, with chief executive Brian Brick revamping ranges and stores and building an online presence since taking over in 2009 after the group made a series of losses.
The business said today that sales at its revamped website, now in its second year of operation, had lifted by 115% for the latest period against last year. The firm now has country specific sits for Ireland, Sweden, Denmark, the Netherlands and Australia.
The firm is in the middle of a store upgrading programme and said it refitted seven shops this year, bringing the total it has updated to 45 out of its portfolio of 135 stores.
Mr Brick said that the weakness in the hire market was "more than offset by the strong performance on retail."
He added that international sales were "now contributing to growth, reflecting our continuing investment in systems and infrastructure."
Cantor Fitzgerald analyst Freddie George said: "The major attraction of the company is the potential for the development of the retail on-line platform, which was successfully launched in January 2013, including a nationwide 'click & collect' offering."
Shares, which have enjoyed a strong performance recently, doubling in value over the last year, slipped almost 2%.