Ocado has revealed strong sales growth this morning in its first trading update as a quoted company, but its shares fell following the update.

Gross sales increased 29.5% to £126.5m in the 12 weeks to August 8 compared to the same period a year ago, and 29.8% to £372.2m in the 36 weeks up to the same date.

Average orders per week grew by almost a quarter to 92,834 over the 12 week period, while average order size fell 1% to £113.59. Gross margins were described as “stable”, while potential sites for the second distribution centre in the Midlands have been identified and negotiations are ongoing.

There was no update on Ocado’s progress towards pre-tax profitability. However, chief executive Tim Steiner pointed to the City consensus at the time of Ocado’s float, indicating the grocer would make a pre-tax profit in 2011.

Chief financial officer Andrew Bracey said: “EBITDA growth continued the trend observed in the first half of the year.”

Ocado’s shares, which had recovered in recent days, fell 4.5% to 150p in early trading following the announcement. They floated at 180p.