April 25 (Reuters) - Packaging company International Paper beat Wall Street's expectations for first-quarter sales on Thursday, capitalizing on higher prices, improved production and a rebound in demand for its products.

Initially buoyed by a surge in online shopping during the pandemic, paper and packaging firms faced a slowdown when economies reopened. However, demand is on the rise again and costs - notably for energy, input, freight and wood - have moderated from previous highs.

Peer Packaging Corp of America reported a quarterly revenue beat on Tuesday from higher pricing, improved production and a recovery in demand for its corrugated packaging products.

Earlier in the year, European packaging giant Smurfit Kappa , said the worst of the slowdown in terms of demand for paper and containerboard seemed behind it.

International Paper's total net sales fell about 8%, to $4.61 billion in the first quarter, but topped analysts' estimate of $4.56 billion, according to LSEG data.

On an adjusted basis, the company's operating earnings came in at 17 cents per share, missing an expectation of 22 cents per share, sending shares down 2% in premarket trading.

The world's leading paper company by revenue, it agreed to an all-share deal to buy DS Smith earlier this month, valuing the British packaging firm at 5.8 billion pounds ($7.2 billion) and edging out an offer by Mondi. (Reporting by Annett Mary Manoj in Bengaluru; Editing by Pooja Desai)