ZURICH (Reuters) - The Swiss government on Thursday warned next week's vote in Britain on whether to quit the European Union is a risk factor for Switzerland's economy.

"A withdrawal of the United Kingdom from the EU, with yet fairly unclear arrangements to be made subsequently, would have consequences on different exchange rates and other financial variables, and probably also on companies' investments and, indirectly, on international trade," the State Secretariat for Economic Affairs (SECO) said in a statement.

Economists fear a "leave" vote could unleash turmoil on global financial markets. Traders in London are readying for all-nighters after polls close late on June 23.

In its economic forecasts which are updated every quarter, SECO said Swiss economic growth for 2016 is now seen at 1.4 percent in 2016, unchanged from a forecast in March. It also kept the same 2017 growth forecast of 1.8 percent.

SECO softened its expectations for deflation this year and sees prices falling 0.4 percent. It had previously forecast deflation of 0.6 percent. SECO expects consumer prices to start rising again in 2017, forecasting inflation of 0.3 percent versus 0.2 percent in March.

The forecasts come ahead of the Swiss National Bank's quarterly policy assessment at 0730 GMT. All 36 economists in a Reuters poll predicted the SNB would keep its target range for three-month Swiss Libor at -1.25 to -0.25 percent.

(Reporting by Joshua Franklin)