Federal NDP Leader Thomas Mulcair suggested the premiers of Saskatchewan, Alberta and B.C. are messengers for Harper when it comes to the impact of the oilsands on the economy.
Mulcair has said the oilsands are artificially inflating the Canadian dollar and hurting the manufacturing sector.
But Wall says Mulcair has his facts wrong and what he's doing is divisive for the country.
The premier says Mulcair should look at new numbers from Stats Canada that show factory shipments rose by 1.9 per cent in March to $49.7 billion, lead by petroleum and coal products.
Wall says he thinks Mulcair is risking Canada's economic advantage for the sake of politics.