Earle McCurdy says the 18 seats that would represent the rural region of the island of Newfoundland isn't enough.
He also says it's irresponsible to reduce so much representation in Newfoundland just months before a general election.
The new boundary map would cut the number of ridings in the province from 48 to 40.
Premier Paul Davis has defended cutting the number of seats, citing about $2.5 million a year in savings.
Under the new map, districts in the Labrador portion of the province would not change.
Andrew Parsons, a Liberal member of the legislature, says it will take some time to examine the proposal to determine what impact it will have.