Discount voucher sites are gearing up for a busy Christmas in the expectation that cash-strapped shoppers will be hunting for festive deals online.

Myvouchercodes.co.uk has signed leading retailers including Argos and House of Fraser for its Christmas discount book, which will be sent to 1 million homes in its first big offline direct mail campaign.

The site attracts about 9 million unique users a month, which it expects will rise to 11 million during the busy Christmas period.

Savoo.co.uk, which specialises in online discounts vouchers, is also investing heavily and claimed that online vouchers are increasingly popular because some shoppers are embarrassed to use discount vouchers in stores.

Savoo chief executive Loren Bendele said the business – owned by US-based Savings.com – has already generated $3.5m (£2.2m) of sales for its UK retail partners this year.

“We want to be a major channel in the UK as we are in the US,” he said. “We mostly deal with online vouchers and customers in the UK are not worried to use them. It is becoming cool to be value conscious.”

Savoo has 4,000 vouchers on its site for brands such as Amazon, Tesco, Figleaves and Debenhams.

“We rank the deals in popularity on the site, so we are a testing ground for retailers on what deals work best,” said Bendele.