The margin is tightening in the nation's closest election race in the Victorian seat of McEwen.

Liberal challenger Donna Petrovich narrowly leads Labor incumbent Rob Mitchell, with just 142 votes separating them at lunchtime Saturday.

This has narrowed from Friday, with almost 85 per cent per cent of the vote counted.

In Victoria's other close contest, between Liberal Sophie Mirabella and independent Cathy McGowan in Indi, the latter's lead is widening.

On Saturday, Ms McGowan led by 805 votes with more than 88 per cent of the ballots tallied.

Mrs Mirabella this week ruled herself out of a cabinet post in the Tony Abbott government, saying her decision allowed the new prime minister to choose his ministry without waiting for the result in her seat.

Counting continues Saturday and Sunday.