* ECB will end 2.55 trillion euro bond-buying programme this year
* Could lift deposit rate to -0.2 pct to start rate hike process
* Escalating trade tensions could push euro higher
* ECB says Nowotny's comments don't represent view of whole Governing Council (Adds ECB comment)
LONDON, April 10 (Reuters) - The European Central Bank could raise its deposit rate first before moving its main interest rate later, policymaker Ewald Nowotny said on Tuesday, sending the euro higher and drawing an unusual rebuttal from the ECB.
Nowotny told Reuters in an interview that the ECB's 2.55 trillion euro ($3.1 trillion) bond-buying programme would be wound down by the end of this year, which would then pave the way for the first rate rise since a fumbled move in 2011.
He called on the ECB to get on with the process to ensure it can take a gradual approach, and to start with the deposit rate, which has been in negative territory since mid-2014.
"I would have no problem with moving from -0.4 percent to -0.2 percent as a first step and then, as a second step, include the (main refinancing) policy rate," said Nowotny, who sits on the ECB's Governing Council. "This is the structure. The exact timing? It's too early to tell you."
The ECB, which rarely comments on statements from individual policymakers, distanced itself from Nowotny's comments.
"Governor Nowotnys views are his own. They do not represent the view of the Governing Council," a spokesperson said. The euro had risen a third of a percent on Nowotny's initial comments.
The ECB is expected to lay out in June or July how it plans to wind down the stimulus programme of bond purchases it has been using to help the euro zone economy over the last three years.
The bank has said the key rate will remain at its current level until "well past" the end of these bond purchases. While policymakers have not provided more specific guidance, several rate-setters have already said they are comfortable with market forecasts of a rate increase around April or May 2019.
"One of the strong arguments for moving perhaps a bit faster (with policy normalisation) is exactly to have some room for manoeuvre if we should see some deterioration in the economic condition," Nowotny said.
"As we see it now, the markets are already expecting this development (ending the bond buying programme)," Nowotny said. "I don't think there's very much preparation needed."
He was also sanguine about the heightened volatility in financial markets since February. "I think central bank policy always has to follow a medium-term strategy," he said, noting the euro zone's recent strong economic growth.
Trade tensions that have been escalating between the United States and China could impact exchange rates, however. Turbulence could lead investors to move money into safe havens, he said.
"For the time being I would rather expect that the euro zone is the safe haven and that of course would have some effect on the exchange rate," he said.
The euro gained 14 percent against the dollar in 2017. ECB chief Mario Draghi in January called the single currency's strength a "source of uncertainty". ($1 = 0.8117 euros) (Reporting by Marc Jones and Helen Reid; Editing by Kevin Liffey and David Stamp)