Why did NZ First vote against?

NZ Herald reports:

Questions were raised about the best use of Parliament’s time today as MPs debated whether to repeal a WWI law that has not been used in 30 years.

The Military Manoeuvres Act was enacted in 1915 to deal with mobilisation for World War I, and enabled the Governor-General to declare any land available for a period specified for military manoeuvres.

National MP Kanwaljit Singh Bakshi launched a member’s bill in 2010 to get rid of the outdated law, and tonight the Military Manoeuvres Act Repeal Bill passed its final reading, 111 votes to eight.

NZ First voted against the repeal. Why?