Andreas Seidl insists McLaren will not write off the forthcoming F1 season in order to focus fully on the sweeping rule changes of 2021.

Key rival Renault is openly admitting that it is directing the bulk of its resources this year not to the 2020 project, but to the big opportunity presented by the next set of regulations.

"We definitely won't do that," Seidl told Auto Motor und Sport.

"We have to keep up the positive momentum we have, and take a step forward in 2020."

However, that doesn't mean McLaren is targeting better than fourth overall in 2020, after finishing behind only Mercedes, Ferrari and Red Bull in 2019.

"I am expecting a hard fight for fourth place again," Seidl said. "That is the maximum that is currently possible in Formula 1 given the current budgets.

"And we still see enough weak spots in the team that we have to work on. So we have to show that we are developing in those areas. That is exactly why it is important to have a good 2020 season.

"It is clear to me that this year will be a balancing act in terms of when we flick the switch fully to 2021. Logically, this will happen earlier than usual," he said.

Seidl admits that the 'big three' teams still have an advantage for 2021, as they are able to spend unlimited amounts of money this year before the budget cap arrives.

"If we look towards the cap, the owners of the team have made clear to us that we can operate on that level. That is a great signal for the team, because we then have the ability to get to the top," he said.

"But that won't happen in 2021. After the start of the new regulations, it will take time for the budget cap to take effect. So I don't expect to be on the podium and having victories until 2023," Seidl added.