Businesses with a turnover of less than £2.8m and fewer than 50 employees can claim 100% tax relief on purchases of computing products until the end of the financial year, when it reverts to the normal rate of 40%.
A recent survey found that 77% of small firms questioned were unaware of the tax benefits available, and 58% would consider bringing forward some IT purchasing to take advantage of it.
The Federation of Small Businesses blamed the government for the lack of awareness of the rebate among small businesses.
A spokesman said, "The buck stops with the government. We think that education and training about IT in this country is lacking and that there are very few sources of advice for small businesses."
Tim Beadle, director of Marketing Improvement, which carried out the survey for CSSG, said, "SMEs' sources of good advice are extremely limited. Government has completely underestimated the scale of the task. If you look at the Kew Associates data, you can see that on a per-employee basis SMEs spend between 10% and 40% of what the corporate sector spends on IT. This is massively holding back the UK's competitiveness."