SINGAPORE - Gushcloud chief executive Vincent Ha on Friday apologised to telcos M1 and StarHub, as well as the public, for a negative marketing campaign it managed for Singtel.

Mr Ha said in an email to The Straits Times: "We regret the recent incidents and how it has affected the industry, our influencers and our clients...We are disappointed in ourselves for the way it turned out.

"We have started a process of auditing our practices, processes and people, to ensure that we can be a good agency and partner to our present and future clients. We aspire to higher standards, values and principles on which we will rebuild trust and confidence," he said.

"In the coming months, we will keep the public and industry partners updated on these initiatives through our website."

Gushcloud, a social media agency, was employed by Singtel in June last year to manage its e-campaign to promote a youth mobile plan.

Last Saturday, blogger Wendy Cheng, better known as Xiaxue, posted on her website a leaked 2014 e-mail from Gushcloud in which it gave instructions to its bloggers to complain about StarHub and M1's network connections and services. Ms Cheng also posted many samples of these published online complaints targeted at the two telcos.

Singtel group chief executive Chua Sock Koong made a public apology to M1 and StarHub on Thursday over the campaign. StarHub and M1 have accepted the apology.

The Infocomm Development Authority is still investigating into whether Singtel had breached Singapore's Telecom Competition Code, imposed on all telecommunications licensees.