The increase on 2005 was measured by surveying 8,000 UK businesses that employed 10 or more people.
The ONS said web sales last year represented 6.5% per cent of the total value of all sales by non-financial sector businesses.
The rapid adoption of ICT was fuelling web sales growth, said the ONS.
It said almost one in five businesses employed ICT specialists last year.
And nearly 99% of businesses with 1,000 or more employees had broadband (DSL or other fixed connections) in 2006, compared with 70.3% of those with 10 to 49 employees.
More than 52% of businesses used the internet to interact with public authorities, such as government departments and local and regional authorities in 2006.