Hamburg coach Thorsten Fink's job is on the line after his chairman lambasted the faltering team's defence on Monday.

Hamburg were drubbed 6-2 at Bundesliga leaders Borussia Dortmund on Saturday, leading to chairman Carl Edgar Jarchow's astonishing public rebuke of his coach.

Jarchow said he expects to see an improvement quickly, or else he and the board may be tempted to act.

"I take the long-term view, but on the board we expect things to be implemented," Jarchow told SID, an AFP subsidiary, on Monday.

"In Dortmund, it was a repeat of the debacle against Hoffenheim -- defence is our weak point and these mistakes must be eliminated.

"That is his (Fink's) job."

Hamburg are 15th -- just above the relegation zone -- after five games, but more worryingly they have conceded 15 goals -- 11 of which came in just two games.

Having been hammered 5-1 at home by Hoffenheim in mid-August, Fink's defence again collapsed against Dortmund, despite recovering from 2-0 down to equalise just after half-time.

With Dortmund's Poland striker Robert Lewandowski and Germany winger Marco Reus, plus new signings Henrikh Mkhitaryan and Pierre-Emerick Aubameyang running riot, Hamburg's defence leaked four goals in 16 minutes during a second-half horror show.

"We were naive and lost almost every one-on-one," fumed Fink after Dortmund peppered the Hamburg goal with more than a dozen shots on target.

Hamburg also capitulated 9-2 at Bayern Munich last March and the Hamburg board are running out of patience with Fink, who took charge in October 2011.

After the Hoffenheim defeat, Fink gave his players two days off, then threw left-back Dennis Aogo out of the squad before he was sold to Schalke 04, while centre-backs Slobodan Rajkovic and Michael Mancienne were told they have no future at the club.

The 4-0 drubbing of Eintracht Braunschweig last month failed to mask Hamburg's defensive frailties and Fink now faces a make-or-break clash against north German neighbours Werder Bremen in the Bundesliga on Saturday.

Jarchow left no doubt that defeat in that game could spell the end for Fink.

"One thing is for sure, that is a very important game for everyone," said Jarchow.

Bremen are just one place above Hamburg in the league and suffered their third consecutive defeat when they went down 3-0 at home to Eintracht Frankfurt on Saturday.

"Everything depends on this game," insisted club captain Rafael van der Vaart.