The white paper on gambling, which was published on Thursday, marks the biggest shake-up of regulation in the sector for nearly 20 years.
The government said online slot machines were a particularly high-risk product, associated with large losses.
The white paper proposes a consultation on stake limits of between £2 and £15 per spin for online slots machines.
However, the government also suggested lower limits and greater protections for 18 to 24-year-olds, who “may be a particularly vulnerable cohort”.
The consultation on limits for younger gamblers will include options of a £2 stake limit per spin; a £4 stake limit per spin; or an approach based on individual risk.