The Prime Minister has hinted at the possibility of an earthquake relief package for Wellington businesses.

Economic Development Minister Steven Joyce and Wellington's mayor Justin Lester are in discussions this morning.

John Key told Mike Hosking he doesn't want to over-promise, but they're working their way towards something.

"It's not quite as straight-forward as Kaikoura where you could see a particular area, but we're not unsympathetic to the issue, we understand there are some concerns," he said.

Mr Key is also denying a lack of urgency when it comes to the road in and out of Kaikoura.

Residents are getting frustrated, as work on the road continues to close it.

Mr Key said while they're being conservative, because they're putting safety first, they're also working as hard as they can to get it back up to standard.

"There's a lot of work happening, you know, there's helicopters sluicing the big slips, there's crews working all over the show."

WATCH THE FULL INTERVIEW ABOVE

Meanwhile, the Prime Minister doubts that there'll be much a turnout in the Mt Roskill by-election.

Mr Key said voter numbers are notoriously low in by-elections, and he doesn't expect this one to be much different.

But he believes his candidate, Parmjeet Parmar, could win Mt Roskill if people do get down to the polls.

"We win the party vote there. Historically what you had is people vote splitting a little bit - voting Goff and National."

Advance voting in the by-election began last week, with Saturday the last day to vote.