AMSTERDAM, March 30 (Reuters) - Polish parcel locker firm InPost on Tuesday predicted further growth in sales and profitability this year, saying it expects a boom in e-commerce sparked by the COVID-19 pandemic to survive the lifting of lockdowns.

InPost expects revenues to climb to between 5.7 billion and 5.9 billion Polish zloty ($1.44 bln- $1.49 billion) in 2021, up by almost a third, while its adjusted operating profit margin is seen rising above 30% from 28.3 % last year.

All numbers include the results of Mondial Relay, the French parcel delivery platform InPost last week said it intended to buy.

InPost last year saw revenues double to 2.5 billion zloty as lockdowns to fight the coronavirus pandemic led to a surge in online sales, which the company does not expect to fade once the disease is under control.

"We see a dramatic shift to the online channel, fuelled as well by merchants. Many of them, such as Inditex, are shutting especially their largest stores and money into the online channel," Chief Executive Rafal Brzoska told Reuters.

"This is a sustainable change that will drive volume across the whole of e-commerce. Being a key tech enabler for merchants, we will definitely benefit."

Local media reports saying Alibaba-owned online retail service AliExpress would install up to 8,000 parcel lockers in Poland put pressure on InPost shares on Monday.

But Brzoska shrugged off worries about increasing competition in InPost's home market.

"We are super confident that we are, and we will be, the number one player in Poland," he said.

"We are creating more and more compelling services embedded in the system, we have the number one mobile app in Poland and we have the density of the network."

($1 = 3.9695 zlotys) (Reporting by Bart Meijer; Editing by Jan Harvey)