A spokesman for Treasury said the percentage costs for Genesis were always going to be higher because it was a smaller float.
The Government had always expected Genesis to be proportionally more expensive and had factored that into its calculation.
The cost of the programme to the Crown was still expected to come in under a 2 per cent target for proceeds raised.
"The Treasury is confident the Crown's share offer programme costs will meet its target of around 2 per cent of sale proceeds."
The spokesman said it was important to note that the IPO costs for Genesis were the estimated maximum costs possible.
A final cost would not be known until after the sell-down was com- pleted. Proportionally the Government's floats have cost less than other IPOs undertaken last year.
They ranged in proceed percentage costs from 4.2 per cent for Z Energy up to 10.8 per cent for the Mad Butcher back door listing.
But they were also much smaller. Z Energy was the largest at $840 million and also cost the most in dollar terms at $35.5 million.
As of the end of 2013 the Government's partial privatisation programme had cost a total of $100.51 million of which $71.886 million was paid for by the Government and $28.623 million was paid for by the companies.
Of the $29 million Genesis bill, $11.6 million is due to be paid for out of the company's coffers and $17.4 million is expected to come from the Crown.
Mighty River Power and Meridian Energy had three investment banks assigned to help sell them while Genesis is being sold by UBS and First NZ Capital which will each receive a base fee of $750,000 and may receive a further $750,000 performance fee if certain targets are met. In addition to that they will also receive 0.3 per cent commission on the value of the shares sold to local institutional investors, 0.6 per cent commission for international institutional investors and 0.1 per cent commission on shares sold in the retail offer which aren't linked to a broker.
NZX broking firms and some trading banks will receive 1.25 per cent commission for selling the shares under the broker firm offer and 1 per cent under the general offer. Two retail offer managers will also be paid $50,000 each.
Genesis float
* $1.35 to $1.65 range for share price
* 1-for-15 loyalty bonus share offer
* April 17 listing on NZX expected.
Read the full Genesis Energy share offer statement here