Central Europe's main currencies mostly firmed slightly on Friday, with a sentiment boost from a newly-agreed Brexit deal offsetting worries about the global economy as China posted weaker-than expected growth in the third quarter.

The twin sagas of Brexit and the trade war between the United States and China have shaped risk sentiment in global financial markets this year, with emerging market assets particularly sensitive to developments.

Markets got a boost on Thursday when EU leaders unanimously backed the new Brexit deal, but British Prime Minister Boris Johnson faces a battle to secure parliament's backing on Saturday if he still hopes to take Britain out of the EU on Oct. 31.

In China, third quarter gross domestic product rose just 6.0% year-on-year, as the trade war with the US hit factory production.

At 0848 GMT the Polish zloty was flat against the euro at 4.2825. The Czech crown was 0.14% stronger at 25.668 while the Hungarian forint firmed 0.12% to 330.69.

"The market is waiting for the final Brexit news, tomorrow's vote in parliament in London... It's a major, major risk event tomorrow," said a Warsaw-based currency trader.

"The zloty is quite strong... I think the scope to move lower in euro/zloty is limited, we've reached the bottom of the range."

In Poland, September industrial output and PPI both beat analysts' estimates, rising 5.6% and 0.9% year on year respectively.

"0.9% is not a level that would cause anxiety, the market reaction seems neutral to me, because the situation on the markets is determined by global factors," said Grzegorz Maliszewski, Chief economist at Bank Millennium.

Czech 10-year yields rose 2.8 basis points to 1.453%, while Polish 10-year paper traded at 2.025%, up almost 1 basis point.

Central European bonds often track western European peers, and eurozone bond yields inched up ahead of Saturday's Brexit vote.

Stocks were mixed with Prague's PX index rising 0.64% while Warsaw's WIG 20 fell 0.56%.

Polish mining company JSW was the worst performer on the WIG 20, falling 3.5% after it reported a drop in coal sales in the third quarter despite an increase in production.