The government hopes the Thailand Online Mega Sale 2013 will boost online shopping to reach more than 90 billion baht this year.
The event, which will run from Nov 26 to Dec 3, will offer discounts of as much as 80% for online products and services.
Deputy Commerce Minister Nattawut Saikuar said the first-ever online discount campaign aims not only to stimulate consumers to buy more online but also to promote e-commerce.
More than 500 websites are participating in the campaign, which is expected to generate sales of more than 500 million baht.
Mr Nattawut said online buyers remain marginal, making up only 10% of 25 million internet users in Thailand.
Pawoot Pongvitayapanu, president of the Thai E-Commerce Association, said the country's online shopping has seen average growth of not less than 20% a year and still has ample room to grow if businesses participate in internet sales campaigns.
"The number of products and businesses made available over the internet remains relatively small," he said.
"More importantly, trust is still a key stumbling block for online shopping growth as Thai consumers in general still lack confidence in making transactions via electronic commerce."
However, in a bold move to build up trust, Chaichana Mitrpant, assistant executive director of the Electronic Transactions Development Agency, said the unit will closely monitor online transactions to ensure international standards and safety.
The agency also plans to set up an online consumer protection centre to increase confidence.
The latest Rakuten Smart Shopping Survey said 78% of 2,000 online shoppers in Thailand, Indonesia, Malaysia and Taiwan in the past 12 months were unhappy with their purchases, showing the need for better product quality and greater details.
Rakuten is Japan's biggest e-commerce company and the owner of Thai marketplace Rakuten Tarad.com.
The survey also found one-third of consumers never or rarely interact with merchants during e-shopping, preferring instead to research products first and decide later whether to buy them.
In Thailand, seller reliability was cited as the main issue in failing to complete online purchases.
The top four criteria specified were quality, detailed photos, clear prices and good return policies.