Even though the visitors lined up defensively in the first half, they created the more clear-cut chances.
The best came in the 21st minute when Robbie Ryan picked out Richard Walker, but with only keeper Alan Fettis to beat he scuffed his shot, enabling Town's number one to make a diving save low to his left.
Macclesfield's Kevin McIntyre then forced Kevin Miller to make a telling save with a 25-yard free-kick.
Miller did even better after 41 minutes when John Miles blasted a low drive towards goal from eight yards and the Rovers keeper's strong hand kept the ball out.
There was controversy in the 44th minute when Rovers appealed for a penalty as Matt Carragher cleared a Craig Disley header off the line.
Moments later David Morley lumped the ball clear from defence for Mike Sheron to nod into the path of Parkin, who buried it from ten yards.
Rovers equalised in the 55th minute when a Steve Elliott free-kick took a slight deflection, tricking Fettis into palming the ball into the roof of his own net.
But Parkin was not to be denied and in the 61st minute he lashed home his 23rd goal of the season with a stunning right-foot drive from 25 yards.
Disley then fired past the post for Rovers before Walker picked out Fettis with a close-range header.
At the other end, Neil Mackenzie hit the post for Macclesfield with a left foot 15-yard drive before Parkin was denied his hat-trick when John Anderson cleared off the line.
Fettis made amends for his early mistake with a competent catch at the death as Elliott blasted a shot through a crowd of players.