Leverkusen sports director Rudi Voeller said 21-year-old Havertz is travelling to London "so that Kai can now sort things out on the ground in London with our support."

Germany coach Joachim Loew said he expected Havertz to sign for Chelsea soon - in what would be a club record transfer of Stg90 million ($A164m) including add-ons.

"We knew that now, today or tomorrow, the final details were meant to be sorted out in his contract with Chelsea," Loew said in a video on the German soccer federation website, adding that Havertz "definitely wants to take this step".

Havertz was an unused substitute when Germany played a 1-1 draw with Spain on Thursday in the Nations League.

Loew said he was aware of risking the transfer if Havertz played and was injured.

The signing of Havertz would likely complete an overhaul by Chelsea that has also seen striker Timo Werner, winger Hakim Ziyech, centre back Thiago Silva and left back Ben Chilwell move to the Londoners.

"We are aware of the importance of this for Bayer 04 Leverkusen and Kai and want to approach this responsibly," Germany's national team general manager Oliver Bierhoff said.

"At the same time it is an honour and a distinction for German football when young German players are in demand at top international clubs."

Havertz last played for Leverkusen in the quarter-finals of the Europa League on August 10, scoring in a 2-1 loss to Inter Milan.

Leverkusen coach Peter Bosz has said he doesn't expect to have Havertz - who scored 12 league goals last season and set up another six - available for the new season.

Australian Associated Press