LONDON: Formula One has rewritten a rule to ensure reduced points are given for shortened races after Red Bull's Max Verstappen clinched his second title in confusing circumstances last October.

The Formula One commission, which groups the 10 teams and governing FIA as well as the commercial rights holder, met in London on Tuesday ahead of next week's season-opening race in Bahrain.

A statement of key decisions -- to be rubber-stamped by the FIA's World Motor Sport Council -- included a change of wording "to ensure that shorter races have reduced points even if they don’t finish with a suspended race."

Last year's rain-hit Japanese race was halted after two laps and resumed more than two hours later with 28 of the scheduled 53 laps completed. Even Verstappen was unsure how many points he had won.

It turned out to be full points, enough for Verstappen to clinch the title with four races to spare. The FIA explained at the time that the reduced points rule only applied to grands prix that were suspended and could not be resumed.

The commission also agreed "to relax the regulation of radio messages to and from the drivers at all times during a competition."

It said a change to wet weather tyres had been approved, with Pirelli producing a new compound that performed better and did not require the use of tyre blankets used to get tyres up to temperature. This would be introduced from Imola in May.

Bahrain, Jeddah, Melbourne, Baku and Miami will have changes to the Drag Reduction System (DRS) zone to make overtaking either easier or harder. Melbourne will have a fourth DRS activation zone.

Teams and engine manufacturers will have a winter factory shutdown in 2023, in addition to the August break.

A cost cap adjustment was agreed to allow teams to spend an extra $1.2 million, on top of a base of $135 million for the season, to reflect the calendar stretching to a record 23 rounds and those added being long-haul and more expensive.

The rules were tweaked also "to allow easier access to the factories for the FIA auditing team, in order to police the adherence of the teams and PU (Power Unit) manufacturers to the financial regulations".

The cost cap was introduced in 2021 to help level the playing field.

The meeting was chaired by Formula One Chief Executive Stefano Domenicali and FIA single-seater director Nikolas Tombazis.

FIA president Mohammed Ben Sulayem, who has agreed to stand back from day to day running of the sport after recent controversies, did not attend.