Officials on Thursday hailed a 5.3 percent increase in statutory minimum wage and potential annual adjustments, but a lawmaker turned his focus on the formula governing the hourly rate, saying it should be reviewed more frequently.

From May 1, workers earning minimum wage will receive HK$42.1 per hour, up from HK$40.

And instead of biennial reviews, the wage level will now be adjusted once a year.

In a Facebook post, Chief Executive John Lee said annual reviews will help the minimum wage keep up with the prevailing situation.

"We are grateful for the input from the labour sector, and thank you again for your contributions to Hong Kong, especially in the aviation industry," he told airport workers in a video.

The formula governing the minimum wage is also updated - while it still takes into account inflation and economic growth, a clause is added so that the rate will not go down - even in times of recession.

Labour minister Chris Sun told an RTHK radio programme that officials will review the formula every five to 10 years.

"The formula needs to be consistent for employers, so we believe that since different sides have come to an agreement, we should stick to it," Sun said.

However, unionist lawmaker Lam Chun-sing proposed on the same programme more frequent reviews to make sure the new formula works well.

"We believe that for the next step, like the MTR's fare adjustment mechanism which is reviewed every five years, the formula should be reviewed at least every five years," he said.

"Since this is being implemented for the first time, perhaps we could make it even sooner, like reviewing it after three years."

Lam, who chairs the Federation of Hong Kong and Kowloon Labour Unions, said while the formula helps workers keep up with basic inflation, it still falls short of improving their livelihood.