The Competition and Markets Authority (CMA) said it proposes to designate Apple and Google's mobile platforms with "strategic market status (SMS)", subjecting them to special requirements under new UK regulations.

An investigation was launched in January into the companies' control over the mobile ecosystems, including operating systems, app stores and browsers.

The CMA described their dominance as "an effective duopoly".

"Apple and Google's mobile platforms are both critical to the UK economy ... but our investigation so far has identified opportunities for more innovation and choice," CMA chief executive Sarah Cardell said in a statement.

Google's spokesman on competition, Oliver Bethell, said the announcement was "disappointing and unwarranted".

If approved, the SMS designation would allow the CMA to require Apple and Google to change how certain mobile services operate, with the aim of offering consumers greater choice.

The regulator stressed that the designation does not imply that these companies have acted anti-competitively.

The final decision is subject to consultation and expected by October 22.

A similar tech competition law from the European Union, the Digital Markets Act, carries the potential for hefty financial penalties.

The CMA in June proposed designating Google with SMS designation in the search engine market due to its dominant position.