Wesfarmers has lifted sales in all its retail businesses in the first half of the financial year, with the strongest growth coming from Coles and Bunnings.

Sales at Coles in the six months to December 31 were $18.3 billion, up 4.7 per cent from the same period in the previous year.

Sales at Bunnings and Office Works in the six months to December were $4.7 billion, up 4.9 per cent from the previous corresponding period.

"The retail businesses continue to improve their customer offers, with record numbers of shoppers visiting our stores during the Christmas period," Wesfarmers chief executive Richard Goyder said in a statement.