The non-bank has told advisers that investors will be allowed to borrow up to 80% LVR, providing a boost to buyers during the Covid-crisis.
The lender previously limited the amount of loans it provided above 70% LVR, as it uses warehouse funding from the main banks.
Resimac eased its criteria after the Reserve Bank scrapped LVR rules earlier this month.
"The decision reflects the easing of speed limits," said Resimac's head of New Zealand Luke Jackson. "We've always been comfortable lending at 80% LVR to investors, but were constrained, and now we're not, and are opening up for prime customers. We're happy to look at more in that space."
Resimac's servicing test rate remains at 6%, one of the lowest in the market.
The move comes as Reismac looks to build market share in the prime investor market.
The lender cut its prime interest rates last month, moving closer to terms offered by the major banks. The firm has a 3.39% two-year fixed loan.
"We like to be seen as an alternative lender now, not someone you see when the banks say no, but a first port of call," Jackson added.
Resimac says it has experienced strong demand since the Covid-19 crisis, with enquiries up 30% between Easter and the end of April.
Like the main trading banks, Resimac also offered hardship requests to existing borrowers following the Covid outbreak and lockdown. It says only one in five customers who made a hardship request took a full six month deferral.
Resimac's decision to do more investor lending comes in contrast to BNZ, which has informed advisers it will only lend up to 70% LVR to investors, despite the end of LVR restrictions.
BNZ will also no longer count borrowers' Airbnb and boarder income, making servicing more difficult.