The news comes after Eurostar's positive reports for business travel back in 2011.
A Eurostar spokesperson told C&IT: "Business travel patterns across all markets are impacted by the prevailing economic climate, and we continue to see a softening in demand for Business Premier travel as organisations maintain a close eye on corporate travel budgets.
"As the only train operator with three classes of service, we are well positioned to cater for the changing needs of our customers. Alongside Business Premier and Standard travel, Standard Premier remains popular amongst price responsive business travellers looking to keep a tight rein on travel expenditure."
Elsewhere, sales revenue for Q1 2013 was up 1% to £213m from £211m in Q1 2012, with passenger numbers stable year-on-year.
Nicolas Petrovic, chief executive of Eurostar, said: "This is an encouraging start to the year in spite of the challenges posed by both the economy and the weather. Our sales revenues have grown during a quarter which saw heavy snowfalls and some of the coldest temperatures on record in the South of England and Northern France. This quarter’s performance is testament to our enduring popularity with regular and first time travellers alike."
Meanwhile, Eurostar’s largest international market, the USA, has shown particularly strong growth in the first three months of the year, up 20%.