LISBON, May 17 (Reuters) - Portugal's largest listed bank, Millennium bcp, reported a 64% rise in first-quarter net profit on Monday, driven by its domestic business, despite losses in a Polish unit and higher impairments and provisions booked due to the COVID-19 pandemic.

Consolidated net profit totalled 57.8 million euros ($70.2 million), while in Portugal alone the bank netted more than 83 million euros, five times more than a year ago.

Net interest income (NII), a measure of earnings on loans minus deposit costs, slipped 2.5% to 376 million euros during the first three months of 2021, the bank said in a statement.

Poland’s Bank Millennium reported last week a quarterly loss of 311 million zlotys ($82.8 million) mostly due to provisions for risks related to foreign currency loans.

"In a very difficult context after a year of pandemic, the favourable evolution (of net profit) was due to the good performance of activity in Portugal," Chief Executive Officer Miguel Maya told a press conference.

In the wake of the pandemic, consolidated impairments and bad loan provisions surged 20% to 242.8 million euros.

Still, the bank reduced non-performing exposures by 830 million euros to 3.1 billion euros in the first quarter from a year earlier.

Portugal's banks have suspended capital and interest repayments on 44 billion euros of corporate and household debt to avoid a jump in bad loans, according to Bank of Portugal data.

Millennium bcp has approved around 8 billion euros in such moratoriums to support families and businesses hit by the pandemic, but 91% of these show no signs of future default, the CEO said.

Although he did not expect "any drama" with the planned end of the moratoriums in September, these will have to be dealt with on a case-by-case basis, he added. ($1 = 0.8232 euros) (Reporting by Sergio Goncalves; editing by Andrei Khalip and Hugh Lawson)