(Reuters) - U.S. manufacturing activity picked up at its briskest pace in more than six years in December, extending a recovery in the factory sector that has spurred the strongest pricing environment for goods producers since 2011 as the coronavirus pandemic upends supply chain networks.

Still, IHS Markit's final manufacturing purchasing managers' survey of a rocky 2020, released on Monday, showed the sector's rebound was uneven. Consumer goods makers saw weaker order flow as COVID-19 infections surged and limited consumer spending, while producers of machinery and equipment noted strong demand in a potential sign of improving business investment, said Chris Williamson, Chief Business Economist at IHS Markit.

IHS Markit said its manufacturing PMI climbed to 57.1 in December from 56.7 in November. The index also improved from its preliminary - or "flash" - reading in mid-December of 56.5, with a reading above 50 signaling expansion in activity.

The index finished 2020 at its highest level since September 2014, with December's gain marking the eighth straight month of improvement after plunging to its lowest in more than a decade in April when the first rounds of business shutdowns to contain COVID-19 were in full swing.

With output moderating to 58.3 last month from 59.2 in November, the headline index's improvement was driven largely by a strong pricing environment, IHS Markit said. Its output price index rose to its highest since May 2011.

"Amid a significant deterioration in vendor performance, cost burdens and selling prices soared, as firms sought to partially pass on higher input prices," IHS Markit said in a statement. "Output expectations moderated slightly, however, as the post-election spike eased and virus cases surged once again."

(Reporting by Dan Burns; Editing by Chizu Nomiyama)