Greek lawmakers are to vote on a package of tough salary and pension cuts as part of measures needed to secure the payout of the debt-ridden country's second international package of bailout loans.

Tuesday's parliamentary vote comes a day after the Standard & Poor's ratings agency downgraded Greece's credit rating to "selective default" over a debt writedown deal with private creditors that is an integral part of the second bailout.

The downgrade had been widely expected, as ratings agencies had said the bond swap with private creditors would constitute a selective default. Once the swap is carried out next month, the agencies are expected to upgrade Greece.

The Finance Ministry said the S&P had "no impact in the Greek banking sector."