Pirelli is planning to introduce a sixth tyre compound for 2018.

Auto Motor und Sport reports that the new, extra compound - a sort of 'ultra ultra-soft' tyre - will be at the softest end of the official F1 supplier's range.

It is also suggested that all the current compounds will be a step softer next year.

"The new tyre and the softer compounds are badly needed," a team member is quoted as saying.

Also being discussed at present is how tyres will be allocated to the teams.

Some are arguing that teams should get free rein to choose from any of the six Pirelli compounds at each race, but Pirelli's Mario Isola is not convinced.

"With free choice, the top teams would choose harder compounds and still get into Q3 and then have a clear advantage in the race," he said.

However, others argue that if there is free choice, smaller teams will be able to select aggressively soft tyres and qualify artificially high up the grid.