A few minutes later, Mr Shearer picked up that theme when the debate over the Mixed Ownership Model Bill began.
He said every New Zealander he'd spoken to in recent months said their biggest concern about the partial privatisation plan was that the price of electricity would rise.
"We know that the three major power companies are actually well and efficiently run. So the only way you can get an efficient company to generate more profit is by putting up the price.''
But Mr English dismissed Mr Shearer's attack as "nonsense''.
The Government has consistently countered concerns about power prices by pointing out more New Zealanders than ever were switching suppliers to find the lowest price.
"Does he seriously believe that hundreds of thousands of New Zealanders are systematically paying more for electricity than they could?''
Mr Shearer's theory about prices "relies on Labour's belief that most New Zealanders are stupidly paying 13 per cent more for their power than they could if they just chose to pay less''.
Meanwhile, the Government went on the attack outside the debating chamber, with SOE Minister Tony Ryall saying Labour had a history of privatising state owned assets, often doing so under urgency in Parliament back in the 1980s and early 90s.
"In just three years, Labour sold over 15 state assets for almost $10 billion to the highest bidders'', he said.
One of National's defences of its asset sales plan is that was open about the policy ahead of the last election.
Mr Ryall said Labour's Phil Goff, Annette King, Trevor Mallard and others voted for asset sales without telling the public about their plans, "the same people who are now criticising the National Government's mandated, long signalled, partial share offer to New Zealanders''.