Mercedes have rubbished suggestions that Lewis Hamilton's horror run of bad luck so far in 2016 may be a conspiracy.

As Nico Rosberg turned his six-race winning streak into an almost unprecedented seven at Sochi, some wondered if reigning champion Hamilton's continuing reliability problems have been more than just bad luck.

"This [suggestion] is bullshit," team chairman Niki Lauda told Sky Sports News, after Hamilton had to start the race 10th following an engine problem identical to the one in China two weeks ago.

Team boss Toto Wolff said that heads are being scratched.

"We have eight engines in circulation, thousands of test kilometres have been driven, but this defect has occurred only twice and always in the same car," he told Auto Motor und Sport.

It is believed that Mercedes is not ruling out a chassis problem that is causing the glitch, but the conspiracy theorists suggest that Hamilton's in-race water leak just as he was catching Rosberg is a further sign of a deliberate plot.

Wolff calls those sorts of people "lunatics".

"The last thing we would do is sabotage Hamilton - he's a great friend to us and we are letting him down," he said.

Indeed, Mercedes demonstrated its valiant efforts to minimise the damage to Hamilton's weekend in Russia after qualifying.

A crucial part - preventing a grid penalty - was flown to Russia overnight aboard a specially chartered jet. The team then enlisted the help of Bernie Ecclestone to ensure that it cleared customs and arrived at the track at 2am.

Further fuel for the conspiracy theorists, however, is that Hamilton's car is this year being serviced by mechanics who formerly worked on Rosberg's side of the garage.

"All of a sudden we swapped for no apparent reason," a downbeat Hamilton recalled on Sunday.

"But that's not the reason we're having these issues. Don't jump the gun," the triple world champion, now 43 points down in the championship, added.

"[Favouritism] has not happened in the last three years and I have no reason to think it's happening now."

Lauda also hit back at the conspiracy theories.

"I hate this talk because we have 1,100 people all trying their best for both cars. These are simple, human mistakes," he said.

The season continues with the Spanish Grand Prix in two weeks' time.