Central European economies Poland and Hungary are expected to expand fairly robustly and in a more sustainable way, particularly for Hungary though it may see a negative impact from the Volkswagen emissions scandal and a slowdown in China, the European Commission said Thursday.

"An escalation of the Volkswagen crisis could affect Hungarian production negatively in the longer run," the executive of the European Union said in its autumn forecast for the bloc. Car manufacturing is the main driver of Hungary's industry.

The slowdown in China and other emerging-market economies also could have indirect negative effects on Hungary through Germany, it added. Germany is Hungary's biggest export market.

At the same time, "arrival of asylum seekers does not fundamentally affect the country's macroeconomic outlook," the commission said.

Hungary became a major transit country this year for migrants from the war-torn regions of the Middle East and Afghanistan. At least 390,941 asylum seekers have entered the country, according to police data, since the start of the year, en route to northern Europe, with hardly any remaining in Hungary.

Hungary's economy, which expanded at an exceptional rate of 3.7% in 2014, will see growth slowing to 2.9% this year and 2.2% in 2016, before picking up again to 2.5% in 2017, the commission said. Projected growth developments largely reflect an expected ebb and recovery in the country's ability to tap the EU for various support funds, a main driver of investment, the commission added.

While its economy continues to expand, Hungary's inflation rate is likely to reach the central bank's 3% inflation target not before the end of 2017, the commission said. Due to lower oil and prices, regulated energy price cuts and lower imported inflation, the commission cut its 2016 inflation forecast for Hungary to 1.9% from 2.5% in the spring, and estimated it at 2.5% on average for 2017.

The Polish economy is expected to keep growing robustly, expanding 3.5% each year through 2017, the European Commission said. That's a slightly higher outlook for the European Union's largest emerging economy compared with the commission's forecast in the spring.

Poland's growth is expected to be driven by domestic demand and private consumption as the domestic labor market is improving strongly, with registered unemployment now below 10%.

Strong export growth is set to continue despite problems with sales to the east, compensated by higher trade with other EU countries.

Poland's public deficit is expected to stay at 2.8% of gross domestic product through 2017, with debt growing to 53.5% of GDP in 2017 from 51.4% expected this year.

Write to Margit Feher at margit.feher@wsj.com; Twitter: @margitfeher and Martin M. Sobczyk at martin.sobczyk@wsj.com